UDK 63/66 ISSN HERBOLOGIA. An International Journal on Weed Research and Control

Transcription

1 UDK 63/66 ISSN HERBOLOGIA An International Journal on Weed Research and Control Proceedings of the 3 rd International Symposium on Weeds Sarajevo, May, 2011 (Part I) Vol. 12, No. 1, May 2011

2 Issued by: The Academy of Sciences and Arts of Bosnia and Herzegovina and The Weed Science Society of Bosnia and Herzegovina Editorial Board Paolo Barberi (Italy) Vladimir Borona (Ukraine) Daniela Chodova (Czech Republic) Mirha Đikić (B&H) Rabiaa Haouala (Tunisia) Zoran Jovović (Montenegro) Gabriella Kazinczi (Hungary) Senka Milanova (Bulgaria) Shamsher S. Narwal (India) Zvonimir Ostojić (Croatia) Lidija Stefanović (Serbia) Taib Šarić (B&H) Dubravka Šoljan (B&H) Štefan Tyr (Slovakia) Editor-in-Chief: Prof. Dr. Taib Šarić Technical Editor: Dr. Mirha Đikić Address of the Editorial Board and Administration: Herbološko društvo BiH (Faculty of Agriculture) Sarajevo, Zmaja od Bosne 8, Bosnia and Herzegovina Phone: , Fax: Published four times a year The price of a copy of the Journal: 15 Papers published in the Herbologia are abstracted and indexed in the CAB International s journal Weed Abstracts and in EBSCO data base The Herbologia can be found on the web site: links: Publications and Herbologia Printed by Štamparija Garmond Graphic, Sarajevo The printing of this journal and organizing of the Symposium on Weeds was financially supported by the Federal Ministry of Education and Science of B&H, Cantonal Ministry of Education and Science, and Federal Ministry of Tourism and Environment, Sarajevo

3 CONTENTS Page 1. T. Šarić: Introductory address T. Šarić, Z. Ostojić, L. Stefanović, S. Milanova, G. Kazinczi, L. Tyšer: The changes of the composition of weed flora in Southeastern and Central Europe as affected by cropping practices S. S. Narwal, R. Haouala: Allelopathic strategies for ecological weed management S. Redţić: The ecology and syntaxonomy of weed vegetation at the Dinaric Alps (w. Balkan) O. Ilić, Lj. Nikolić: Ecological characteristics of ass. Panicogalinsogetum Tx. et Beck in potato crop Š. Týr, T. Vereš, J. Smatana: Temporal dynamics of invasive weed species in the Slovak Republic G. Baeva, R. Nakova: Weed infestation research in winter wheat fields in northeast Bulgaria S.Hadţiablahović, S. Redţić, Z.Bulić: New species in the alien flora of Montenegro D. Petrović, N. Herceg, Z. Kovačević, I. Ostojić: Distribution of tree of heaven species Ailanthus altissima (Mill.) swingle in Herzegovina G. Kazinczi: Climate change and weeds in Hungary N. Galzina, M. Šćepanović, M. Goršić, I. Turk: Allelopathic effect of Abutilon theophrasti Med. on lettuce, carrot and red beet O. Nikolić, S. Ţivanović Katić, M. Jelić: Comparison between allelopathic and competitive relationships between some weed species and small grains by grain harvest index aspect...133

4 13. O. Nikolić, S. Ţivanović Katić, M. Jelić, I. Đalović: Relation of yield and grain harvest index in wheat by weed influence aspect M. Đikić, D. Gadţo, T. Gavrić, V. Šapčanin, A. Podrug: Dormancy and weed seed germination B. Konstantinović, M. Meseldţija, B. Konstantinović: Mapping of invasive species Ambrosia artemisiifolia L. by ambrosia spot marker software B. Konstantinović, M. Meseldţija, M. Korać, N. Mandić: Horizontal and vertical seed distribution under different field crops Instruction to Authors in Herbologia

5 Herbologia Vol. 12, No. 1, 2011 ADDRESS OF THE CHAIRMAN OF THE SCIENTIFIC COMMITTEE OF THE 3rd INTERNATIONAL SYMPOSIUM ON WEEDS Taib Šarić Dear colleagues, ladies and gentlemen, dear guests, It is my honour and pleasure to open, on behalf of the Organizing and Scientific Committee, the 3rd International Symposium on Weeds. I want to greet all the colleagues and guests and wish them successful work at this meeting and a pleasant stay in Sarajevo. Welcome all our colleagues who came from 13 countries on three continents: from India, Tunisia, Ukraine, the Czech Republic, Slovakia, Hungary, Bulgaria, Slovenia, Croatia, Serbia, Kosovo, Macedonia, and Bosnia and Herzegovina. Our last Symposium was held eight years ago in this same hotel. Few of you were present at the meeting. During that period, a lot of progress has been made in both weed science and weed management practice in the world. Some news and experiences from that we are going to hear at this Symposium. The First International Weed Conference in Sarajevo was held 38 years ago. I had the honor to be the chairman of the Organizing Committee at the event. At the end of the Conference we held the Foundation Assembly of the Yugoslav Weed Science Society, which later played a very important role in our weed science and profession. The Society started publishing the journal Fragmenta Hebologica Jugoslavica. In Sarajevo, a postgraduate study in weed science was established, the first one of that kind in this region. In this town, several books on weeds were published, among them being the first Weed Atlas in colors, which had five editions so far, as well as the book on weeds and herbicides, which has been printed in eight editions. Weed congresses and symposia started to be held regularly. Intensive research and cooperation developed among weed scientists and their institutions within our former country and farther. The founded Society became a member of the European Weed Research Society in which some ot its members took an active role. We can not, at this occasion, avoid mentioning and giving due tribute for their merits for establishing and development of the Society and weed science, particularly to professors Josip Kovaĉević from Zagreb, Kojić and Ĉuturilo from Belgrade, Stanković and Ĉanak from Novi Sad, Lozanovski from Skopje, Mrs. Miljeva Kaĉ from Slovenia and others, most of whom are unfortunately not alive today. They contributed to establishing and promoting of weed science in this region and to raising generations of capable successors, who further developed this scientific field and professon. I had the honour to be one of the founders of that Society and its President and I

6 T. Šarić can express my pleasure for very good cooperation which lasted among us for years and decades. Thanking to such a cooperation we could successfully carry out big international research projects. Within one among them, the Yugoslav-American project on biological weed control, our team of researchers from Sarajevo made a significant contribution in the research of allelopathy between crops and weeds, as a new biological way of weed control. By that fact Sarajevo became a pioneer of that kind of research in this region. Meetings like this one are important not only for acquainting with new scientific achievements and for the exchange of experience, but also for personal acquaintance, fostering closer ties and for further cooperation. Therefore it gives us great pleasure to have today with us some distinguished scientists from various countries. Some people ask what the red flower or plant in our symbol or logotype represents? Some of you have in it recognized cockle (Agrostemma githago), but they ask: why just that one? Here is the explaination: Long time ago, when our agriculture was primitive, the cockle used to be a very frequent and dangerous weed in our crops, particularly in small grains. Therefore for a long time there was a sentence that "there is no cereal without cockle." However, nowadays there is no more cockle, only the proverb remained. By introducing contemporary cropping practices, particularly cleaning of crop seeds by cockle cylinder or assorting engine, cockle seeds, which had been spreading by cereal seeds, were removed from crop seeds. Together with it, from crop seeds were purged some other once frequent and noxiuos weeds, such as Melampyrum arvense, Lolium temulentum and some Lathyrus and Vicia species, which are today found very seldom or not at all. It is our desire that many other dangerous weed species, which today inflict huge losses to agriculture and some other activities, disappear from our fields, so that they could not make harm any more. Of course, we do not wish them to disappear completely; they should remain in the nature because all plants are important members of ecosystems. They enrich biodiversity and gene pools and their genes might once assist in improving some species or cultivars of cultivated plants. We only wish to prevent losses caused by them, and we wish to utilize them whenever possible. Although weeds all the time pose harmful pests in crops, by development of weed science and profession we succeed to minimize these losses and to enable achieving high, profitable and easier production in agriculture. The aim of this and similar scientific conferences is the exchange the knowledge and experience so that we can improve weed control to the limit that weeds will no more be an obstacle to agriculture to produce enough food and fibers for the present and ever increasing human population and to play the role it should have to. 2

7 Introductory address We wish that this gathering today and tomorrow be at least a modest contribution to that goal. Thank you. 3

8 Herbologia Vol. 12, No. 1, 2011

9 Herbologia Vol. 12, No. 1, 2011 THE CHANGES OF THE COMPOSITION OF WEED FLORA IN SOUTHEASTERN AND CENTRAL EUROPE AS AFFECTED BY CROPPING PRACTICES Taib Šarić 1, Zvonimir Ostojić 2, Lidija Stefanović 3, Senka Deneva Milanova 4, Gabriella Kazinczi 5, Ludek Tyšer 6 1 Academy of Sciences and Arts of Bosnia and Herzegovina, Sarajevo, tsaric@bih.net.ba 2 Faculty of Agriculture, Zagreb, Croatia. E.mail: zostojic@agr.hr 3 Maize Institute Zemun Polje, Belgrade, Serbia. lida@euner.rs 4 Plant Protection Institute, Kostinbrod, Bulgaria, sdmilanova@yahoo.com 5 Kaposvár University, Department of Botany and Plant Production, H-7400 Kaposvár, Guba S. str. 40. Hungary. kazinczi,gabriella@ke.hu.vcf 6 Czech University of Life Sciences Prague, Dept. of Agroecology and Biometeorology, Kamýcká 957, Prague 6 - Suchdol, Czech Republic, tyser@af.czu.cz Abstract The composition of weed flora in an area is affected by climate, soils, and agricultural practice. As the practice is concerned, the choice od crops and cropping practices, particularly soil tillage, fertilization, planting method, seed rate and purity, herbicide application, and crop rotation are of the most importance. In some cases, the crop seed cleaning is of major singnificance on weed structure and abundance. Due to these factors, weed flora in an environment is not static, it is changing with some weed species disappearing while new invasive species are spreading and replacing them. The abundance of certain species is changing as well. In six countries of Southeastern and Central Europe, the composition of weed flora in the last decades has greatly changed primarily due to changing cropping practices. In various countries the changes are different depending on the type of change of agricultural practices. Bosnia and Herzegovina In the last hundred years, the structure of weed flora in Bosnia and Herzegovina has greatly changed. Komša (1928) and Vasković (1931, 1933) published their studies on their extensive research of weed distribution all over Bosnia. Our studies of weeds on croplands across Bosnia half a century later enabled us to compare the changes over five decades (Šarić, 1979, 1980; Šarić et al., 1991, 1992, 1999)). The main findings are as follows:

10 Šarić et al. A number of weed species that were most frequent and harmful in the first three decades of the 20th century, completely or almost completely disappeared from the arable land. These are: Conyza canadensis, Agrostemma githago, Melampyrum arvense, Bidens tripartita, Verbena officinalis, Prunella vulgaris, Centaurea scabiosa, Cichorium intybus, Lolium temulentum, Sambucus ebulus, Arctium lappa i Rubus caesius. Some of them were thriving only on neglected grasslands or on wastelands. Vicia and Lathyrus species, as well as Agrostemma githago, Lolium temulentum, and Melampyrum arvense also diseppeared primarily due to cleaning crop seeds by machines. The other reasons for greatly reducing the above species in the last 5-6 decades were: better and deeper soil tillage, better fertilization, denser crop stands, crop rotation, and herbicide application. In the first five decades, more frequent weed species in maize became: Agropyron repens, Chenopodium album, Chenopodium polyspermum, Amaranthus retroflexus, Setaria spp., and in wheat: Galium aparine, Veronica persica, Stellaria media, Lamium purpureum, Ambrosia artemisiifolia, etc. Herbicide application in the second half of the 20 th century inflicted a significant change in weed associations. Triazine herbicides controlled succeptible species, while resistant perennial ones took their place. Among them are particularly Agropyron repens, Potentilla reptans, Mentha arvensis, Convolvulus arvensis, Equisetum arvense, Cirsium arvense, Rorippa sylvestris, Sonchus arvensis, Stachys palustris. In that period, more frequent species in maize became: Agropyron repens, Chenopodium album, Chenopodium polyspermum, Amaranthus retroflexus, Setaria spp.; and in wheat, Galium aparine, Veronica persica, Stellaria media, Lamium purpureum, and Ambrosia artemisiifolia. In the last three decades, Sorghum halepense, Avena fatua, Abutilon theophrasti, Xantium strumarium, and Datura stramonium have spread into new areas. Common ragweed (A. artemisiifolia) is particularly troublesome and quickly spreading because of enormous abundance of these seeds. The main reasons for rapid spreading of Avena fatua and some other weeds are: contaminated crop seeds with weed seeds, unclean farm machines such as drills and combine harvesters, neglecting crop rotation, the use of farmyard manure not fully rotted, etc. Combine harvesting of small grains stimulated the spread of small and light seeds such as Apera spica-venti and Ambrosia artemisiifolia. 6

11 The changes of the composition of weed flora in Southeastern and Central... Cocle (left) disappeared from the cereal fields in Bosnia, while ragweed (right) spread over many croplands and wastelands Some weed species, which infested cropland earlier, such as noxious and invasive Avena fatua, Sorghum halepense, and Ambrosia artemisiifolia, have recently been found in larger numbers in formerly infested and in new areas. Ambrosia artemisiifolia has especially spread to areas where it has not been before. In the last few decades, Sorghum halepense and Ambrosia artemisiifolia spread from the Posavina (in the north) to the south (Šarić, 1980). Jonsongrass and wild oats are relatively resistant to control. Common ragweed is troublesome because of enormous abundance of seeds, which creates a great problem in crop practice where it did not occur before in the large area of Bosnia and Herzegovina. One reason for numerous populations of some weeds and their rapid expansion was the war in Bosnia ( ). During the war, weeds were not controlled and they disseminated and expanded freely (Šarić et al., 1999). Nevertheless, weedeness on arable land in Bosnia and Herzegovina today is smaller than 7-10 decades ago, due primarily to better cropping practices, particularly to crop cleaning seeds and applying herbicide. Apart from many drawbacks of spreading new invasive weed species, especially crop yield losses, new invasive species might have some benefits. They are enriching the genofond of the existing plants. Gene banks with the genes of new weed species could possibly be used in the future in crop breeding by genetic engineering as sources of desirable genes to be transfered for attaining resistance against plant deseases, pests, etc., as well as for 7

12 Šarić et al. hardiness towards low or high temperatures, drought, salty or flooded soils, etc. References KOMŠA, A., 1928: Korov Sarajevskog polja. Rad Fitopatološkog zavoda u Sarajevu, str MIKULKA, J., D. CHODOVA, 1999: Long-term changes in weed societies in the Czech Republic. Proc. 11th Symp. EWRS, Basel. ŠARIĆ, T., 1980: Promjene sastava korovske vegetacije na oranicama Bosne u posljednjih 50 godina. I kongres o korovima. Banja Koviljaĉa. ŠARIĆ, T., 1979: Dolgoroĉnie tendencii izmenenija sostava sornjakovoj vegetaciji v pšenici i kukuruze. XXI Georgikon napok, Keszthely. ŠARIĆ, T., Z. ELEZOVIĆ, 1991: Širenje divlje zobi u Bosni. Fragmenta herbologica, Vol. 20, No ŠARIĆ, T., Z. ELEZOVIĆ, Š. MUMINOVIĆ, 1992: Ekspanzija divljeg sirka, ambrozije i smrdljive koprive u Bosni. III kongres o korovima, Banja Koviljaĉa. ŠARIĆ, T., M. ĐIKIĆ, D. GADŢO, Z. ELEZOVIĆ, 1999: Praktiĉne posljedice promjene biodiverziteta korovske flore u BiH pod uticajem agrotehnike. Radovi Polj. fak. Univ. u Sarajevu. Vol.XLIV, br. 48. Sarajevo. VASKOVIĆ, G., 1931: Prilog poznavanju korovne flore Kraljevina Jugoslavije. Rad Fitopatološkog zavoda u Sarajevu, sv. II, str VASKOVIĆ, G., 1933: Prilog poznavanju korovne flore Kraljevine Jugoslavije. Deo II. Korovna flora Vrbaske banovine. Ibidem, sv. IV, str Croatia One of numerous definitions of weeds says that weed is any plant other than the crop sown (Brenchley, 1920) that grows spontaneously in a habitat greatly modified by human action (Harper, 1944). Cultural practices over thousands of years have changed the nature of cultivated plants and their unwanted associates-weeds (Kovaĉević, 1958). Since human began deliberately to produce cultural plants, they are constantly striving to achieve higher and better yields. Applying modern, more efficient cropping practices, human activity directly affects the composition of weed flora. In recent decades the introduction of fertilizers, pesticides (and herbicides particularly), and powerful agricultural machinery significantly altered agricultural weed flora. There are few exact indicators that accurately define or describe the weed flora in the last hundred years. Kodinec (1930) notes next species as the most widespread annual weeds in Croatia: Avena fatua, Agrostemma githago, Centaurea cyanus, Papaver rhoeas, Setaria viridis, Viola tricolor, Capsella bursa-pastoris, Medicago lupulina, Daucus carota, Raphanus raphanistrum, Sinapis arvensis, Vicia spp. The most common perennial species were: Triticum (Agropyron) repens, Cirsium 8

13 The changes of the composition of weed flora in Southeastern and Central... arvense, Equisetum arvense, Leontodon taraxacum (T. vulgaris) and Achillea millefolium. Ĉmelik (1943) notes as the most common weeds in small grains Veronica spp., Myosotis arvensis, Stellaria media, Lamium purpureum, Centaurea cyanus, Agrostemma githago, Delphinium consolida, Cirsium arvense, Papaver rhoeas, Convolvulus arvensis and Galium aparine. In summer crops the most common were Raphanus raphanistrum, Sinapis arvensis, Matricaria chamomilla, Ranunculus spp. and Agropyron repens. Kovacevic (1958) gives a detailed overview of weeds by crops. At that time in small grains the most common were: Agrostemma githago, Anthemis arvensis, Centaurea cyanus, Convolvulus arvensis, Papaver rhoeas, Lathyrus spp., Vacaria pyramidata, Cirsium arvense, Raphanus raphanistrum, Sinapis arvensis, Thlaspi arvense, Adonis aestivalis, Anagalis arvensis, Ranunculus arvensis, Melampyrum arvense, Polygonum convolvulus. In row crops the most common were Amaranthus retroflexus, Atriplex patula, Cirsium arvense, Galinsoga parviflora, Sonchus arvensis, Lepidium draba, Equisetum arvense, Matricaria chamomilla, Echinochloa crus-galli, Polygonum spp., Solanum nigrum, Hyosciamus niger, Vicia spp. In the 1950 s, in cereal crops were introduced translocation (hormonal) herbicides based on the 2,4-D, and in the 1960 s triazine herbicides in maize. After that there were great changes in the composition of weed flora. Table 1. shows the changes in weed flora in row crops in Croatia for the period since 1969 until Certain weed species such as Raphanus raphanistrum, Sinapis arvensis, Lepidium draba, Equisetum arvense, Centaurea cyanus and Sonchus arvensis are almost completely suppressed. In contrast, species Ambrosia artemisiifolia, Echinochloa crus-galli, Chenopodium album, Amaranthus retroflexus, Xanthium strumarium, Abutilon theophrasti, Setaria spp, Sorghum halepense, Cirsium arvense and Convolvulus arvensis are increasingly present. Similarly, in winter cereals (Table 2.) Agrostemma githago, Centaurea cyanus, Raphanus raphanistrum, Sinapis arvensis, Vicia spp, Lathyrus spp, Lithospermum arvense, Lepidium draba, etc. are completely lost. In contrast, as dominant species are Galium aparine, Stellaria media, Matricaria chamomilla, Polygonum spp, Apera spica-venti, Convolvulus arvensis, Anthemis arvensis, etc. In recent years in Croatia there has been a tendency towards less intensive soil tillage systems as alternative to conventional tillage. As mentioned, the introduction of new tillage practices commonly causes changes in the weed composition and abundance of weed population. In a 9-year research, in winter wheat the annual species had a higher population and dry biomass in conventional tillage with mouldboard plough at cm depth than with reduced tillage practices that included loosening 9

14 Šarić et al. with chisel plough at cm depth and disk harrowing at 8-10 cm depth. Further, the dry weight shares of annual weed populations were 63%, 50% and 41% with mouldboard ploughing, chisel ploughing and disk harrowing, whereas the perennial weed dry weight shares were 3%, 26% and 44%, respectively (Kneţević et al., 2008). Over the time period, the weed spectrum in disk harrowed plots changed. There was an increase of perennial populations that included the species of Calystegia sepium, Convolvolus arvensis, Cirsium arvense and Equisetum arvense. (Kneţević et al., 2003a). On the other hand, some annual broad-leaved species such as Fallopia convolvulus, Lamium purpureum, Polygonum aviculare, P. lapathifolium and Sonchus oleraceus showed a tendency to increase densities with mouldboard plough tillage (Kneţević et al., 2007). (In the Table 1: OD = order of dominance 10

15 The changes of the composition of weed flora in Southeastern and Central... Table 1. The most important weeds of row crops in Croatia based on the results of field trials (165) set up for scientific investigation and official herbicide registration purposes conducted every five years from 1969 to 2009 (Ostojić et al.) Year 1969 OD 1974 OD 1979 OD 1984 OD 1989 OD 1994 OD 1999 OD 2004 OD 2009 OD Weeds/Number of trials CHEAL 81, ,7 4 93, ,8 3 82,6 1 71,4 3 ECHCG ,5 4 93,3 2 87,3 1 73,9 2 85,7 1 AMBEL 15, , ,8 2 73,9 3 71,4 2 POLPE ,3 3 85,7 3 87,5 3 73,3 4 60,3 4 52,2 4 57,1 4 AMARE 81,8 4 62,5 7 69,2 6 42, , ,7 6 52,2 5 57,1 5 CHEPO 76,9 5 57,1 5 37, ,6 5 47,8 6 28,6 8 SETGL 72, ,6 4 26, , ,5 7 42,9 6 CONAR 90,9 3 62,5 8 53,8 9 42,8 9 18, ,3 6 30,2 7 34,8 9 POLAV 54, , , , , ,4 10 CIRAR , , , ,7 8 3, ,1 12 ABUTH 7, , ,3 11 SONAR ,5 9 15, , ,8 20 6,7 28 4, ,4 14 SOLNI 45, , , , , ,4 15 SETVI 23, ,7 2 31, , , ,6 7 CYNDA 14,3 21 3, SORHA 14,3 20 6,3 35 6,7 22 7, ,3 10 CALSE 23, , , ,3 20 1,6 39 8,7 18 ANAAR 45, ,5 6 61,5 7 28, ,7 10 9, HIBTR 9, , ,8 8 6, , ,3 11 XANST 28,6 9 AGRRE 81, , ,8 7 6, ,7 24 6,

16 Šarić et al. Table 2. Order of the most important weed species in cereals according dominance in field trials on 232 locations from 1985 to 2000 (Ostojić et al.) No. Weed Number of locations 1 GALAP STEME MATCH 82 4 POLPE 77 5 APESV 70 6 CHEAL 68 7 CONAR 65 8 ANTAR 62 9 AMBEL CIRAR POLAV VIOAR MYOAR 35 References BENE, I. 2010: Brojnost i uĉestalost uskolisnih korova u okopavinskim kulturama u razdoblju od godine. Završni rad. Zagreb, str. 29 ĈMELIK, S Korovi i njihova štetnost i korist. Zagreb, str. 52 GALZINA, N., BARIĆ, K., ŠĆEPANOVIĆ, M., GORŠIĆ, M., OSTOJIĆ, Z. 2010: Impact of common rageweed (Ambrosia artemisiifolia L) on weed flora of row crops during last four decades in Croatia. IX Alps-Adria Scientific Workshop. Növénytermelés 59 (Suppl. 4): KNEŢEVIĆ, M., B. STIPEŠEVIĆ, LJ. RANOGAJEC, I. KNEŢEVIĆ, 2008: Long-term effects of soil tillage on weed populations in winter wheat. Herbologia 9, KNEŢEVIĆ, M., B. STIPEŠEVIĆ, I. KNEŢEVIĆ, Z. LONĈARIĆ, 2007: Weed populations of winter wheat as affected by tillage and nitrogen. Ekológia 26, KNEŢEVIĆ, M., M. ĐURKIĆ, I. KNEŢEVIĆ, O. ANTONIĆ, S. JELASKA, Effects of tillage and reduced herbicide doses on weed biomass production in winter and spring cereals. Plant Soil. Environ., 49, KODINEC, G Korov i njegovo uništavanje. Zagreb, str. 16 KOVAĈEVIĆ, J Korov ili draĉ u gospodarstvu. Zagreb, str. 88 KOVAĈEVIĆ, J. 1958: Najrašireniji korovi obraċivanih površina. Hemizacija poljop., 16, 9-18, Beograd. KOVAĈEVIĆ, J. 1967: Utjecaj herbicida na promjenu korovne flore i neki novi herbicidi u nas. Biljna zaštita, XI, 3-4, 57-65, Zagreb. LOJEN, N. 2003: Brojnost i uĉestalost korovne flore u strnim ţitaricama u razdoblju godine, Diplomski rad. Zagreb, 120. OSTOJIĆ, Z. i sur. (neobjavljeno) Sluţbeni izvještaji poljskih pokusa o ispitivanju herbicida u razliĉitim kulturama u razdoblju od godine ŠEHRIĆ, A. 2000: Brojnost i uĉestalost vrsta u kukuruzu u razdoblju od godine. Diplomski rad. Zagreb,

17 The changes of the composition of weed flora in Southeastern and Central... Serbia The weed associations in maize crops under conditions of intensive cropping practices are dynamic and changeable systems. Many factors affect the maize weed flora composition (climate, type of soil, cropping practices like tillage, crop rotation, crop density and herbicides). Among them, herbicides have been the most important and the main measure in maize weed control. Herbicides are a powerful tool by which components of agrobiocoenosis are significantly affected. A long term application of herbicides affected changes in weed flora. Essentially these changes are adjustment of weed associations to environmental conditions and anthropogenic activities. The changes in the floristic composition of weeds in maize crops used to happen periodically, which had been related to the application of herbicide active ingredients that have been used in practices. The 42-year long study on weed associations in maize crops under intensive cropping practices and the herbicides application shows significant changes in the floristic composition of weed associations. The changes occurred as a reduction in the number of broad-leaf weeds and also as an increased spread of annual and perennial species of the Poaceae family (Šinzar et al.,1996). Table 1. Distribution of weed species during the period Year of investigation Weed species Total number of species Perennial broad-leaf species Perennial sp.of Poaceae fam Annual sp.of Poaceae fam Annual broad-leaf species Total number of perennial sp Total number of annual species Total number of broad-leaf sp Total number of Poacea species The highest number of weed species was recorded in 1952, which is considered as an initial status (Kojić, 1953). Assuming that cropping practices, and especially the application of herbicides, have been quantitatively and qualitatively intensified since 1952, it can be ascertained that weed associations have been reducing in maize crops. The number of 13

18 Šarić et al. weed species has abruptly reduced, but then it increased again and approached the initial value. At the same time the floristic composition of associations have changed and a relative participation of certain types and ecological groups of weeds has also changed (Šinţar et al., 1998). The first changes in the weed flora composition in maize crops were observed in results on the long-term application of herbicides belonging to triazines. They were manifested by the elimination of susceptible weed species. For instance, species Sinapis arvensis L., Fumaria officinalis L., Stellaria media (L.) Vil., Arctium lappa L. and Stachys annua L., were registered only in the beginning of the introduction of herbicides into the maize growing practices, while later on, they were not registered in any of observed locations. These weeds are replaced by annual broad-leaf species, less susceptible to herbicides activities, as well as, by newly introduced species Ambrosia artemisiifolia L., Abutilon theophrasti Medic, Xanthium strumarium L. The following annual broad-leaf weeds are permanently distributed in maize crops: Amaranthus retroflexus L., Chenopodium album L., Datura stramonium L., Bilderdykia convolvulus (L.) Dum., Heliotropium europeum L., Hibiscus trionum L. and Solanum nigrum L. (Stefanović, 1987). The analysis of a great number of floristic screenings (500) from 19 observed regions of Serbia showed that species of the family Poaceae prevailed in the total weed distribution in maize crops, and that their distribution varied over locations (Stefanović and Šinţar, 1992). Out of totally registered species of this family in the observed regions, annual species Panicum crus-galli L., Setaria glauca (L.) P.B. and Digitaria sanguinalis (L.), and perennial species Sorghum halepense (L.) Pers., Cynodon dactylon (L.) Pers. and Agropyrum repens (L.) Beauv. are permanently distributed. Among distributed weeds in maize fields in Serbia Sorghum halepense (L.) Pers. was predominant species in weed associations. Due to its intensive vegetative regeneration, as well as, its high resistance to numerous herbicides, Sorghum halepense (L.) Pers. was spreading rapidly, especially in maize fields (Šinţar and Stefanović, 1994). Convolvulus arvensis L. and Cirsium arvense (L.) are most distributed perennial broad-leaf species in maize fields in Serbia (Šinţar and Stefanović, 1993). With the introduction of post emergence herbicides (sulfonilureas) in maize weed control, beside better control of all weeds, especially grass ones, a new weed problem occurred. The analysis of weed flora carried out in maize fields during the ten-year period ( ) shows that the total number of weeds species varied. The total number of species was increased in comparison with the previous period, and the composition of distributed species was altered, which pointed out to qualitative and quantitative changes in floristic composition of weed associations in maize crops (Simić and Stefanović, 2006; Stefanović and Simić, 2006). 14

19 The changes of the composition of weed flora in Southeastern and Central... Table 2. The most important weed species in maize fields in Zemun Polje (Stefanović, 2001) Weed species Number % Number % Amaranthus retroflexus L Chenopodium spp. L Datura stramonium L Solanum nigrum L Sorghum halepense (L.) Pers Convolvulus arvensis L Panicum crus-galli L Setaria sp. (L.) P.B Atriplex patula L Hibiscus trionum L Sinapius arvensis L Cynodon dactylon (L.) Pers Diplotaxis muralis (L.) D.C Stachys annua L Digitaria sanguinalis (L.) Scop. Amaranthus albus L Ostale vrste Total Weed number Species most often registered in this location during the ten-year period were: Amaranthus retroflexus L., Chenopodium hybridum L., Datura stramonium L. and Solanum nigrum L, and their participation in the total weed coverage in maize crops has been significantly increased in recent times. The comparison of gained results and results on the study of weed flora carried out in this region in the previous period points out to the changes in the floristic composition in maize crops. In recent times, the species Ambrosia artemisiifolia L. stood out by its aggressiveness among distributed species. Due to its biological traits, and also due to favourable soil-climatic conditions, this species has been constantly spreading, and its participation in the weed population in row crops has been permanently increasing. In the last 60 years this species has spread over the whole territory of Serbia (Josifović, ). The population of the species A. artemisiifolia L. today differs in the number, density and coverage in maize associations in dependence on specificity of ecological properties of the habitat and as a weed plant presents a great problem to agricultural producers (Vrbniĉanin and Malidţa, 2008). 15

20 Šarić et al. Changes in the floristic composition and structure of weed associations are constant because of high adaptability of weeds. Bearing in mind the significance of monitoring changes in weed flora in dependence on time for more rational weed control, a systematic screening of weed flora in different crops has been initiated in Serbia (Stefanović at al., 2002; Vrbniĉanin et al., 2008a,b, 2009). References JOSIFOVIĆ M., : Flora SR Srbije I - IX. Srpska Akademija Nauka i Umetnosti. Odeljenje prirodno-matematiĉkih nauka, Beograd. KOJIĆ M., Ispitivanje zakorovljenosti nekih ţita u okolini Beograda. Arhiv za poljoprivredne nauke, 13-14, str SIMIĆ M., STEFANOVIĆ L., 2006: Analiza korovske zajednice kukuruza Zemun Polja. Arhiv za poljoprivredne nauke, 67, str STEFANOVIĆ L., 1987: Zakorovljenost useva kukuruza severoistoĉne Srbije. Izd. Institut za kukuruz Zemun Polje, Beograd. STEFANOVIĆ L., ŠINŢAR B., 1992: Zastupljenost vrsta familije Poaceae u korovskim zajednicama useva kukuruza Srbije. Zbornik radova Ĉetvrtog kongresa o korovima, Banja Koviljaĉa, str STEFANOVIĆ L., 2001: Promena korovske flore kukuruza pri primeni herbicida. Zbornik radova I meċunarodnog Simpozijuma Hrana u 21. veku, Subotica, STEFANOVIĆ L., VRBNIĈANIN S., SIMIĆ M,. 2002: The importance of weed flora mapping in the region of Serbia. Acta herbologica, 11, str STEFANOVIĆ L., SIMIĆ M., 2006: Changes in maize (Zea mays L.) weed community during the last ten years. Plant Science, Bulgaria, 43, str ŠINŢAR B., STEFANOVIĆ L., 1993:. Zastupljenost i rasprostranjenost višegodišnjih vrsta korova u usevu kukuruza u Srbiji. Acta herbologica, 2, str ŠINŢAR B. AND STEFANOVIĆ L., 1994: Rasprostranjenost i zastupljenost Sorghum halepense Pers. u korovskim zajednicama useva kukuruza Srbije. U: Zaštita bilja danas i sutra. Izd. Društvo za zaštitu bilja Srbije Beograd-Zemun, ŠINŢAR B., STEFANOVIĆ L., STANOJEVIĆ, M., 1996: Prilog poznavanju višegodišnjih promena floristiĉkog sastava korovske zajednice useva kukuruza. Zbornik radova sa petog kongresa o korovima, Banja Koviljaĉa, str ŠINŢAR B., STEFANOVIĆ L., STANOJEVIĆ, M., 1998: Promene korovske flore i vegetacije kukuruza pri višegodišnjoj primeni herbicida. Pesticidi, 13, VRBNIĈANIN S., MALIDŢA G., STEFANOVIĆ L., ELEZOVIĆ I., STANKOVIĆ- KALEZIĆ R., MARISAVLJEVIĆ D., RADOVANOV-JOVANOVIĆ K., PAVLOVIĆ D., GAVRIĆ M., 2008a. Distribucija nekih ekonomski štetnih, invazivnih i karantinskih korovskih vrsta na podruĉju Srbije. I deo: Prostorna distribucija i zastupljenost osam korovskih vrsta. Biljni lekar, XXXVI: VRBNIĈANIN S., MALIDŢA G., STEFANOVIĆ L., ELEZOVIĆ I., STANKOVIĆ- KALEZIĆ R., MARISAVLJEVIĆ D., RADOVANOV-JOVANOVIĆ K., PAVLOVIĆ D., GAVRIĆ M., 2008b: Distribucija nekih ekonomski štetnih, invazivnih i karantinskih korovskih vrsta na podruĉju Srbije. II deo: Prostorna distribucija i zastupljenost devet korovskih vrsta. Biljni lekar, XXXVI: VRBNIĈANIN S., MALIDŢA G. (2008). Ambrosia artemisifolia: Pregled sa posebnim osvrtom na u Srbiji. Zbornik rezimea IX Savetovanja o zaštiti bilja, Zlatibor,

21 The changes of the composition of weed flora in Southeastern and Central... VRBNIĈANIN S., MALIDŢA G., STEFANOVIĆ L., ELEZOVIĆ I., STANKOVIĆ- KALEZIĆ R., JOVANOVIĆ-RADOVANOV K., MARISAVLJEVIĆ D., PAVLOVIĆ D., GAVRIĆ M., 2009: Distribucija nekih ekonomski štetnih, invazivnih i karantinskih korovskih vrsta na podruĉju Srbije. III deo: Prostorna distribucija i zastupljenost osam korovskih vrsta na podruĉju Srbije. Biljni lekar, XXXVII: Bulgaria The application of herbicides, among other factors, has affected the composition of weed flora, especially in forming resistance biotypes and the available of compensatory processes. In Bulgaria the first investigation of weed populations in arable lands was done in the period from 1950 to 1962 (Kolev, 1963). Later, during the periods and the national weed surveys were performed. According to the weed assessment, Fetvadjieva & Dechkov (1973) concluded that some species infesting winter cereal crops had increased their density considerably in comparison with the period , such as: Polygonum convolvulus L., Galium tricorne Stokes, Galeopsis tetrahit L., Apera spica-venti (L.), Avena fatua L., Alopecurus myosuroides Huds., Lolium temulentum L., Anthemis arvensis L., Matricaria perforate Merat., and others. After the democratic processes in 1989 in Bulgaria, the weed flora underwent serious changes. The arable land was separated and returned to the ex-owners. Roadside near small fields, margins, uncultivated fields created a large opportunity for troublesome weed species to form abundant populations. Observations in these areas showed that density of some weed species have increased considerably as: Sorghum halepense L., Cirsium arvense L., Cirsium ligulare Boiss, Cichorium intybus L., Sonchus arvensis L., Artemisia sp., Chondrilla juncea L., Carduus acanthoides L., Lactuca serriola L., Centaurea solstitialis L., Onopordum acanthium L. Dipsacus laciniatus L., Cardaria draba (L.) Desv., Rumex crispus L., Daucus carota L., Xanthium strumarium L., Xanthium italicum Moretti, Conyza canadensis (L.) Cronq., Conium maculatum L., Convolvulus arvensis L., Cephalaria transsilvanica (L.) Roemer, Tragopogon dubius Scop., Kochia scoparia (L.) Schrader, Heliotropium europaeum (L.), and others. Some of the above weed species easily spread to the crop fields. It was found that the density of Sorghum halepense, Cirsium arvense, Cichorium inthibus, Conyza canadensis, Xanthium strumarium, Xanthium italicum, Cardaria draba, Conium maculatum, Rumex crispus increased in field crops (Milanova et al., 2002; Fetvadjieva & Milanova, 2002; Milanova & Dimitrova, 2003; Milanova & Dimitrova, 2004; Milanova et al. 2007). It is interesting to note that, for the conditions of Bulgaria, Sorghum halepense has been included in the list of quarantine weeds up to 1962 (Kolev, 1963). Now this species occurred in over of 200,000 ha. The 17

22 Šarić et al. wide and calamitous spreading of cocklebur (Xanthium strumarium) over the farming area in Bulgaria was attributed to the compensatory processes (Fetvadjieva & Milanova, 1998). The gradual warming up of the climate as well as human activities also produce their effect on the weed composition. In the last years the dry soil conditions were reflected in the distribution of some weed species. Most of the species, whose population has increased, belong to the group of xerophytes (Milanova & Gusev, 2001; Milanova & Dimitrova, 2003). The data from national weed survey during showed the increasing expansion of Cirsium arvense, Elymus repens (L.) Gould., Alopecurus myosuroides, Avena fatua, Avena sterilis ssp. ludoviciana (Durieu), Myagrum perfoliatum, Sinapis arvensis, Hibiscus trionum, Veronica hederifolia, Galium aparine, Abutilon theophrasti, Viola arvensis Murray, Buglossoides arvensis (L.) I.M.Johnston, Polygonum aviculare L., Convolvulus arvensis and others. In 2007, at the extreme high air temperatures and soil dry conditions, the most frequent annual weeds in the fields were: Xanthium strumarium, Amaranthus retroflexus, A. hybridus, Hibiscus trionum, Conyza canadensis, Lactuca serriola, Solanum nigrum, Portulaca oleracea, Polygonum aviculare. New species which were previously unknown for the conditions of Bulgaria have appeared in the last two decades, e.g. Ambrosia artemisiifolia L., Iva xanthiifolia (Nutt.), Panicum capillare L., Phytolacca americana L., Commelina communis L., Fallopia japonica (Houtt.) Ronse Decr., Solidago canadensis L. Since the last national survey in 1979, an aggressive spread of some weed species in both uncultivated and cultivated fields was evident. It can be concluded that, due to climate and economic changes happened in the past decades, weed species abundance is increasing becoming a serious problem. Modifications in the choice of crops in rotations, chemical and mechanical weed control, fertilization, soil management, sowing time and technique, purification of seeds and agricultural land separation are the main reasons for these negative processes. References KOLEV, I., 1963: Weeds in Bulgaria, BAS, Sofia, 566 pp. FETVADJIEVA, N. & Z. DECHKOV, 1973: Results of weed survey in Bulgaria of cultivated lands, Plant protection, 23, (9), FETVADJIEVA, N., S. MILANOVA, 1998: Cocklebur advancing on our fields. Plant protection, (5), MILANOVA, S. & CH. GUSEV, 2001: Insufficient rainfall increased the danger of some weeds. Plant protection, (3), MILANOVA, S., V. NIKOLOVA, TZV. DIMITROVA, 2002: The Canadian fleabane is a real threat. Plant protection, (8-9),

23 The changes of the composition of weed flora in Southeastern and Central... FETVADJIEVA, N. & S. MILANOVA, 2002: The Johnson grass is always on the agenda. Plant protection, (8-9), MILANOVA, S.D., TZV. DIMITROVA, 2003: Weed population changes in Bulgaria some trends and problems. 7 th EWRS (European Weed Research Society) Mediterranean Symposium 2003, Adana/TURKEY, MILANOVA, S., V. NIKOLOVA, 2004: Hoary Cress. Plant protection, (10), MILANOVA, S., G. BAEVA, R. NAKOVA, S. MANEVA, L. CHAVDAROV, G. STOIMENOVA, T. VELICHKOVA, 2007: Some changes and trends in the weed communities in the last years in Sofia region. Proceeding of 9 th Symposium on Flora of Southeastern Serbia and Neighbouring Regions, Nis, September 01-03, 2007, Serbia, Hungary In the last 62 years, weed scientists have paid special attention to the detection of changes in the arable weed flora in Hungary. There were five national weed surveys carried out between 1947 and 2008 years. Places for the weed surveys were determined on the basis of genetical soil map of the country. Vicinities of 202 settlements were selected including all soil types important for the arable plant production. Regarding that winter wheat and maize production are traditions in Hungary (both of them are grown around 1 million hectares) surveys had to be done in maize and wheat crops and on wheat stubbles. In order to compare the results of weed surveys carried out at different times, the methods and locations of the surveys did not change (Novák et al., 2009). Sunflower is the third most important crop in Hungary after winter wheat and maize. In this crop a study surveyed the weed vegetation, by sampling 46 fields across the country in 2009 (Pinke and Karácsony 2010). Beside these, the spread of the 12 most noxious weed species was surveyed earlier (between 1986 and 1989) by the herbologists (Tóth and Török 1990). Between 2002 and 2004 years the first national weed survey of plantations (fruit and vineyard) was also carried out (Dancza et al., 2005). All weed surveys were done after the method of Ujvárosi. The cover percentages of the weed species were determined and beside these, the plant phenological stages and GPS coordinates of the sample quadrats were also recorded. There are special factors which have an effect only on a given weed species, while other factors can influence the weed flora more generally. The most important general factors are the following: 1.Increase in waste lands; abandoned areas have considerably increased, resulting in the intensive spread of some weed species, especially Ambrosia artemisiifolia. 2.Increase in land speculatively purchased. 3.Dispersal of weed seeds and vegetative propagules (in case of perennials) due to the transportation of arable soil during field working on new land. 4.Increase in contractual agricultural work; machines for soil cultivation and harvest transport weed seeds and vegetative 19

24 Šarić et al. propagules. 5.Lack and/or general decline in chemical weed control; this has resulted in the rapid spread of noxious perennial weeds of young forests. 6.Interactions among weed species (allelopathy, competition). The abundance of weed species with strong competitive ability and allelopathy (e.g. Abutilon theophrasti, Asclepias syriaca, Cyperus esculentus, Xanthium spp.) has increased. 7.Lack of proper stubble treatments after cereal harvest. 8.Continuous rising costs of chemical weed control. 9.Poor weed management programmes; lack of knowledge.10.withdrawal of herbicide active ingredients in the European Union has resulted in gaps in chemical weed control (e.g. Pre Pant Incorporation (PPI) applications in maize, sugarbeet and sunflower). 11.Inappropriate soil cultivation and agrotechnics (seed-bed preparation is not adequate, edges of the agricultural fields have become weedy, no or poor use of crop rotation). 12.Non-certified seeds for sowing may be heavily infested with weed seeds. 13.Appearance of herbicide resistant weed biotypes (e.g. atrazine-resistant Amaranthus). 14.Global warming and the lack of strong winter frosts may greatly favour the spread of some invasive alien weeds.15.extended use of non-persistent post-emergence herbicides allow the later appearance of large weed populations. The Fifth National Weed Survey was carried out in at 195 locations in wheat and maize fields across Hungary. Summarizing and evaluating the data, the following results were found: The total weed cover decreased in winter wheat up to the end of the 1980s. This was the effect of large-scale intensive production and chemical weed control. Similar trends could be seen in maize up to In after considerable increases in weed cover - the total weed cover exceeded that of the 1950s. In the last twenty years mainly due to the change in the ownership of lands total weed cover has greatly increased, both in wheat and maize. The weed cover in maize is especially high, compared with that of 62 years ago. In spite of the considerable decrease in cover percentage, Matricaria inodora has kept its first place in the dominance order of weeds in winter wheat. The importance of Ambrosia artemisiifolia has increased; it is the second most important weed with a cover of 1.94% (Table 1.).Among winter annuals, the importance of Apera spica-venti has increased. Its cover is almost twice as high as 20 years ago. The cover of other winter annual, Galium aparine has decreased, but it is nevertheless the 5 th most important weed of winter wheat. The cover percentage of perennials is still high. Although the cover of Cirsium arvense has decreased, the cover of Convolvulus arvensis and Agropyron repens has increased and all three perennials are in the ten most important weed species of wheat. Chemical weed control and early stubble treatment has resulted in the decrease of typical stubble-weeds like Stachys annua. On wheat stubbles, the incidence of A. artemisiifolia was the highest (with a cover of 6.44 %). Its 20

25 The changes of the composition of weed flora in Southeastern and Central... coverage was reduced nearly by 1% compared with that of the Fourth National Weed Survey carried out ten years ago. Their cover has generally decreased, but considerable increases in cover percentage of Setaria glauca, S. viridis, Digitaria sanguinalis, Amaranthus chlorostachys and Hibiscus trionum have been observed. The cover percentage of the most important perennials, like C. arvense, C. arvensis, S. halepense and A. repens have also increased. On the basis of the results of weeds surveys carried out in maize, the three most important weed species are Echinochloa crus-galli, A. artemisiifolia and Chenopodium album. Echinochloa crus-galli was the most important weed species of maize in early summer, while A. artemisiifolia had the highest cover value (8.72%) in maize at the end of summer. Ambrosia artemisiifolia cover increased nearly by 1%, as compared with that of the Fourth National Weed Survey. The rapid expansion of several annual grass weeds, like S. glauca, Panicum miliaceum, D. sanguinalis and S. viridis was observed. Further increase of Abutilon theophrasti and volunteer sunflower was also recorded. The importance of A. repens and C. arvense increased, while that of C. arvensis decreased. The cover percentages of the first three weed species of maize (A. artemisiifolia, E. crus-galli and C. album) are especially high on the summarized list of weeds in winter wheat and maize. Ambrosia artemisiifolia remains the most important weed in Hungary (Table 1.). Its mean cover increased up to 5.33%. The increase in cover of annual grass weeds is also seen on the summarized list. The abundance of S. glauca, P. miliaceum, D. sanguinalis and S. viridis increased due to their spread in row crops. Apera spica-venti is a more important weed, even on the summarized list, than before. The importance of perennial C. arvense considerably increased in the last 20 years and nowadays it is the 4 th most important weed of Hungary. The increase of A. repens continues. Average cover percentage of A. artemisiifolia has increased both in wheat and maize in the last ten years. A slight 1 % decrease was observed on wheat stubbles, as compared with data of ten years ago. This was probably due to the summer drought of 2007, which was not favourable even for A. artemisiifolia. Spread of A. artemisiifolia could be observed towards the north. Surveyed locations where A. artemisiifolia is not yet detected are only found in the northern part of Hungary. Besides A. artemisiifolia, special attention should be paid to the prevention of spread of other invasive alien weed species. The results of surveys in the last 20 years confirmed an increase in the spread of A. theophrasti, P. miliaceum and Asclepias syriaca. Cyperus esculentus is also a rapidly spreading weed in Hungary. 21

26 Šarić et al. No significant changes in the importance of Datura stramonium were observed over the last ten years. The importance of G. aparine has decreased; its cover percentage in winter wheat dropped almost to the level of 20 years ago. The importance of Avena fatua, Xanthium strumarium, X. italicum and X. spinosum have also decreased on arable lands in the last ten years. The abundance of Iva xanthiifolia also decreased at the surveyed locations. In the last ten years, the importance of S. halepense has increased, except in late summer maize, although it dropped back to the 11 th place in the dominance order of weeds. Stubbles and maize fields are good habitats for A. artemisiifolia and other allergenic weeds, allowing them to release their pollen over extended periods. Therefore, early and adequate stubble treatments and effective weed management applied in maize fields are essential. Weed surveys were carried out on non-controlled sample areas, so the data presented here do not show the actual but the potential weed infestation of the studied areas if there were no weed control. In sunflower the most abundant species and their mean cover values were: Ambrosia artemisiifolia (9.99%), Chenopodium album (5.59%), Convolvulus arvensis (3.68%), Xanthium italicum (2.37%), Echinochloa crus-galli (2.28%), Cirsium arvense (2.24%), Panicum miliaceum ssp. ruderale (2.22%) and Setaria pumila (2.13%) (Pinke and Karácsony 2010). Based on the results of weed surveys in plantations we can conlude that the proportion of perennial weeds is very high. In vineyards and apple plantations Elymus repens and Convolvulus arvensis are dominant. The abundance of Calamagrostis epigeios is high regardless to the type of plantations. Among winter annuals, Stellaria media is common not causing considerable effect on fruit yield and the presence of Ambrosia artemisiifolia is frequent in cherry orchards (Dancza et al. 2005). In sunflower the most abundant species and their mean cover values were: Ambrosia artemisiifolia (9.99%), Chenopodium album (5.59%), Convolvulus arvensis (3.68%), Xanthium italicum (2.37%), Echinochloa crus-galli (2.28%), Cirsium arvense (2.24%), Panicum miliaceum ssp. ruderale (2.22%) and Setaria pumila (2.13%) (Pinke and Karácsony 2010). Based on the results of weed surveys in plantations we can conlude that the proportion of perennial weeds is very high. In vineyards and apple plantations Elymus repens and Convolvulus arvensis are dominant. The abundance of Calamagrostis epigeios is high regardless to the type of plantations. Among winter annuals, Stellaria media is common not causing considerable effect on fruit yield and the presence of Ambrosia artemisiifolia is frequent in cherry orchards (Dancza et al. 2005). 22

27 The changes of the composition of weed flora in Southeastern and Central... Table. 1. The most important arable weeds of Hungary based on the results of national weed surveys (Novák et al. 2009) (OD: order of dominance) Weeds OD Cover % OD Cover % OD Cover % OD Cover % OD Cover % Ambrosia artemisiifolia 21 0, , , , ,3300 Echinochloa crus-galli 9 0, , , , ,2542 Chenopodium album 3 1, , , , ,6635 Cirsium arvense 2 2, , , , ,7724 Setaria pumila 7 1, , , , ,6324 Convolvulus arvensis 1 7, , , , ,4829 Amaranthus retroflexus 17 0, , , , ,4183 Tripleurospermum inodorum 66 0, , , , ,1634 Datura stramonium 177 0, , , , ,9675 Panicum miliaceum 199 0, , , , ,9600 Amaranthus chlorostachys 105 0, , , , ,9229 Apera spica-venti 56 0, , , , ,9100 Elymus repens 27 0, , , , ,8768 Sorghum halepense 94 0, , , ,8213 Galium aparine 137 0, , , , ,6169 Fallopia convolvulus 14 0, , , , ,5981 Persicaria lapathifolia 29 0, , , , ,5798 Helianthus annuus 206 0, , , , ,5514 Hibiscus trionum 25 0, , , , ,5369 Consolida regalis 19 0, , , , ,

28 Šarić et al. References DANCZA, I., TÓTH, Á., SZENTEY, L., BENÉCSNÉ BÁRDI, G., DOMA, CS., HÓDI, L., HORNYÁK, A., KŐRÖSMEZEI, CS., MADARÁSZ, J., MOLNÁR, F., NOVÁK, R., SZABÓ, R., UGHY, P., VARGA, L First national weed survey of plantations in Hungary. 51 st Plant Protection Scientific Day, Budapest, p.60. NOVÁK, R., DANCZA, I., SZENTEY, L., KARAMÁN, J. (2009): Arable Weeds of Hungary. FIFTH NATIONAL WEED SURVEY ( ). Ministry of Agriculture and Rural Development, Budapest 95pp. TÓTH, Á., TÖRÖK, T. (1990): Country-wide weed survey of dirty dozen. Ministry of Agriculture and Rural Development, Budapest 113pp. PINKE, GY., KARÁCSONY, P. (2010): Weed survey of sunflower fields in Hungary. Növényvédelem 46 (9): Czech Republic In the Czech Republic have also occurred significant changes in the composition of weed communities in recent decades (Kühn, 1987, Kropáĉ, 1988, Kohout et al., 2003, Lososová & Simonová, 2008, Mikulka et al., 2009, Tyšer et al., 2009). The changes occurred not only in species composition, but also in species abundance. In this country, it is shown that on the intensively farmed areas retreated around 100 species and subspecies of weeds. A decrease from down to 7-10 species has been observed in the individual stands of field crops. In many areas and crops only 2-3 weeds have been harmful. In the second half of the 20 th century, with the development of largescale farming, gradually receded or even disappeared species, which can be cleaned from crop seed or are strictly monitored by the control of seed quality. They do not tolerate dense crop stands at a higher level of fertilization; do not tolerate balanced environmental conditions of the site; have a pronounced life cycle. They are sensitive to the active ingredients of long-used herbicides, etc. Such species as Agrostemma githago, Cuscuta epilinum, Lolium temulentum, Adonis flammea, Scandix pecten-veneris, Bromus secalinus, Bupleurum rotundifolium, Caucalis platycarpos, Stachys annua, Conringia orientalis, Erysimum repandum, Arnoseris minima, etc. Many of these weeds are included in the red and black lists of endangered plant species which are protected to conserve the species richness of the flora. However, at the same time several "new" species has spread, which are now common and important part of our field weed vegetation (mainly Echinochloa crus-galli and Amaranthus retroflexus in relation to the introduction of large-scale production of maize). 24

29 The changes of the composition of weed flora in Southeastern and Central Europe.. Reduction of weed species number was not always associated with a decrease in the level of weed infestation. In crops, mostly weeds which were better suited to to cropping practices used, have remained. Under limited competition from other species they excessively proliferate and still cause considerable problems in weed control. These are mainly Elytrigia repens, Cirsium arvense, Avena fatua, Apera spica-venti, Galium aparine, Tripleurospermum inodorum, Rumex obtusifolius, Echinochloa crus-galli, Amaranthus retroflexus, etc. Since 1989, changes in the political system in the country have also been reflected in the new farming systems. The basic trends of current field production include the cultivation of a narrow spectrum of so-called cash crops, especially cereals and oilseed rape. This situation is obvious in increased presence of winter weeds (Apera spica-venti, Galium aparine, Viola arvensis, Veronica spp., etc.) in oilseed rape. Cruciferous weeds and species difficult to be controlled by herbicides (Thlaspi arvense, Descurainia sophia, Viola arvensis, etc.) spread. Reduced soil tillage (minimalization) promotes a number of persistent and perennial weeds (Cirsium arvense, Elytrigia repens, Artemisia vulgaris, Taraxacum spp., etc.) and also annual grass weeds (Apera spica-venti, Bromus sterilis). Long-term and large-scale use of the same herbicide or herbicides with the same mode of action leads to a proliferation of species tolerant to these herbicides (growth herbicides - Galium aparine, Tripleurospermum inodorum, Avena fatua, sulphonylureas - Viola arvensis, etc.) and also promotes the emergence of resistance in so far susceptible weeds (in the past such as Amaranthus retroflexus, Conyza canadensis to triazine, most recently Apera spica-venti to sulfonylureas (Nováková et al., 2006)). The high level of harmfulness is evident in the case of the volunteer plants, i.e. self-set plants from the previous year's crop which become established as weeds in the current crop (volunteers of oilseed rape and sunflower in root crops, cereals volunteers in winter oilseed rape, etc.). Today, the agrophytocoenosis are entered by new, alien, so-called adventitious species. Most of these are recently spreading fast - Amaranthus powellii and weedy forms of Panicum miliaceum in root crops, Abutilon theophrasti in sugar beet and Consolida orientalis in winter cereals. In the warm lowland areas also Kochia scoparia occurs in root crops in a smaller scale (mainly as a weed problem on the railways) and Solanum physalifolium (Holec et al., 2004). Very severe problems are caused by cross-breeds of Beta species (weed beet). It is a form of annual beet originated from hybridization of cultural beet (Beta vulgaris ssp. vulgaris) and wild beets (sea beet, B. vulgaris ssp. maritima) (Soukup et al., 2002). In connection with minimum tillage and other reasons such as lack of interest of local agricultural land, unclear ownership and lack of financial resources in the 25

30 Šarić et al. agricultural sector, some ruderal species such as Lactuca serriola and Conium maculatum significantly increase on a local scale. In certain areas, particularly in the lowlands along the rivers, the major spread on agricultural land of the genus Bolboschoenus, especially B. planiculmis and B. laticarpus has been observed (Mikulka & Zákravský, 2007). The list of today's most problematic species can not be complete and in different regions and farms are rather significant differences related to specific environmental conditions and used agricultural measures. Finally, it should be also mentioned that in recent years, constantly developing new directions in farming systems (integrated and organic), which can contribute under certain conditions to the recovering of agrophytocoenosis, leading to increase in species diversity and the return of some rare weed taxa in the field, although sometimes in conjunction with the increase the overall level of weed infestation. References HOLEC J., SOUKUP J., JURSÍK M. & HAMOUZ P. (2004): Invasive weed species on arable land in the Czech Republic. Z. PflKrankh. PflSchutz, Sonderh. 19: KOHOUT V., TYŠER L., HOLEC J. & SOUKUP J. (2003): The influence of changes in crop sowing area on the composition of weed communities on arable land in the Czech Republic. Herbologia 4: KROPÁĈ Z. (1988): Veränderungen der Unkrautgemeinschaften in der Tschechoslowakei und die Konsequenzen für die landwirtschaftliche Praxis. Wiss. Z. Univ. Halle 37: KÜHN F. (1987): Frequenzveränderungen der Unkrautarten in Mähren Wiss. Z. Univ. Halle 36: LOSOSOVÁ Z. & SIMONOVÁ D. (2008): Changes during the 20th century in species composition of synanthropic vegetation in Moravia (Czech Republic). Preslia 80: MIKULKA J., KORĈÁKOVÁ M., BUREŠOVÁ V. & ANDR J. (2009): Changes in weed species spectrum of perennial weeds on arable land, meadows and pastures. Plant Protect. Sci. 45 Spec. Issue: MIKULKA J. & ZÁKRAVSKÝ P. (2007): Biologie, ekologie a moţnosti regulace kamyšníků na zemědělské půdě. Metodika. VÚRV, Praha. NOVÁKOVÁ K., SOUKUP J., WAGNER J., HAMOUZ P. & NÁMĚSTEK J. (2006): Chlorsulfuron resistance in silky bent-grass (Apera spica-venti (L.) Beauv.) in the Czech Republic. Z. PflKrankh. PflSchutz, Sonderh. 20: SOUKUP J., HOLEC J., VEJL P., SKUPINOVÁ S. & SEDLÁK P. (2002): Diversity and distribution of weed beet in the Czech Republic. Z. PflKrankh. PflSchutz, Sonderh. 18: TYŠER L., HAMOUZ P., NOVÁKOVÁ K., NEĈASOVÁ M. & HOLEC J. (2009): Changes in weed communities on selected areas with 30 years interval. Scientia Agric. Bohem. 40:

31 The changes of the composition of weed flora in Southeastern and Central Europe.. Aknowledgement: This work was supported by the Ministry of Education, Youth and Sports of Czech Republic - project MSM

32 Herbologia Vol. 12, No. 1, 2011

33 Herbologia Vol. 12, No. 1, 2011 ALLELOPATHIC STRATEGIES FOR ECOLOGICAL WEED MANAGEMENT Shamsher S. Narwal and Rabiaa Haouala* Allelopathy Journal, 101, Sector-14, Rohtak , INDIA, *Higher Institute of Agronomy, Chott Meriem, Department of Biological Sciences and Plant Protection, (UR03AGR04), University of Sousse, 4042-Chott Meriem, Sousse, Tunisia E- mail: Abstract The indiscriminate use of pesticides, including herbicides, is causing many problems such as environmental pollution and development of tolerance/resistance in pests (insects, nematodes, pathogens and weeds). Therefore, to overcome such problems, research is needed on following aspects of crop interference: (a) In the world about 500 domesticated plant species are grown as crops and these plants offer a great scope for selection of weed smothering species. (b) Within the promising crops, their varieties may be screened for smothering potential. (c) The genes responsible for production of smothering allelochemicals may be identified and possibly transferred to new varieties of the same or other crops using latest techniques of biotechnology so that plants could produce their own herbicides. (d) Research efforts may be directed to utilize microbial and fungal toxins to control weeds. (e) New and cheap synthetic analogues of natural products having greater selectivity, stability and efficacy to control weeds may be developed. (f) The agronomical practices (sowing time, plant population, row spacing, crop geometry, crop mixture/intercropping) may be further improved to provide competitive edge to the crops over weeds. (g) Crop rotations with allelopathic crops to control weeds may be developed. In view of the numerous problems arising from the chemical weed control, questions have been raised about the continuous use of herbicides. Hence, alternative approaches free from such problems needs to be considered. Use of crop allelopathy and allelochemicals for weed control is a sound alternative provided more information is generated. Crop interference and allelochemicals may be used in future to partially/fully replace herbicides to save our planet Earth and future generations from ill effects of present hazardous herbicides. 1. Introduction Allelopathy is a new and potential area of research. The term allelopathy was coined by Prof. Hans Molisch in 1937, which indicates

34 Narwal and Haouala stimulatory/inhibitory biochemical interactions between the plants including micro-organisms. The allelopathy research started after the end of II World War i.e. near 1950's. During the last 60 years ( ), allelopathy research had been conducted in diverse fields. Hence, International Allelopathy Society in 1996 broadened its definition: Allelopathy refers to any process involving secondary metabolites produced by plants, microorganisms, viruses and fungi that influence the growth and development of agricultural and biological systems (excluding animals). It has been shown that allelopathy plays a major role in various disciplines of agricultural and biological sciences and could be used for pest (weeds, insects, nematodes, pathogens) management. Sustainable agriculture aims at long-term maintenance of natural resources and agricultural productivity with minimal adverse impact on the environment. It emphasizes optimal crop production with minimal external inputs, reducing dependence on commercial inputs (fertilizer and pesticides) and substituting them with internal resources and relying on sustainable practices which could maintain the productivity over long periods. Research has shown that allelopathic practices may meet all these requirements. Hence in future, allelopathy may provide a basis to sustainable agriculture (organic, alternative, regenerative, biodynamic, low input or resource conserving agriculture). To achieve the goals of sustainable agriculture, current research involves, plant breeding, soil fertility, tillage, crop protection and cropping systems. Allelopathy being an important phenomenon in agriculture, its research is also important in sustainable agriculture [Chou (1983), Ramakudzibga (1991), Waller (1987)]. Thus for sustainability, future weed control practices must minimize or stop the use of herbicides and use allelopathic strategies and other practices for weed management. Indiscriminate use of herbicides for weed control during the short span of last 50 years has resulted in serious ecological and environmental problems as under: (A) Increasing incidence of resistance in weeds to important herbicides (Gressel, 1985) (Tables 1, 2, 3) such as S-triazines (Forney et al., 1985) and dinitroanilines (Mudge et al., 1984). (B) Shifts in weed population (a) to species that are more closely related to the crops that they infest e.g. wild oat (Avena fatua L.) in oat, shattercane (Sorghum bicolor L. Moench) in sorghum (S. vulgare Pers.), wild okra (Abelmoschus esculentus L. Moench) in cotton (Gossypium hirsutum L.) and red rice in rice both Oryza sativa L. and (b) minor weeds have become dominant. For example, in crop fields many major weeds suppress Cyperus rotundus and keep its population under control, but after their chemical control, the competitors of C. rotundus have been minimized and thereby it has become a dominant weed. 30

35 Allelopathic strategies for ecological weed management (C) Greater environmental pollution (FAO, 1990) and health hazards (a) particularly from surface and groundwater contamination, which is used for human and livestock consumption, for example in USA, the groundwater contains sizeable quantity of alachlor and atrazine widely used herbicides (3) and (b) from their inhalation during handling and application. (D) Toxic residues of herbicides pollute the environment and may prove hazardous to even future generations. (E) Some agricultural commodities may contain minute quantities of herbicide residues, with long-term adverse effects on human and livestock health. Because of these reasons, serious ecological questions about the reliance on herbicides for weed control has been raised. FAO (FAO, 1997) Expert Consultation Group on Weed Ecology and Management has expressed great concern about the problems associated with the use of herbicides for weed control and has recommended minimising or eliminating use of herbicides with alternative strategies viz., allelopathy (Narwal, 1997), reduced doses of herbicides to maintain weeds at economic threshold level and use of clean crop seed etc. Table 1. Resistance to herbicides. I. Grassy weeds most resistant to herbicides Weed spp. Resistance to Countries modes of action Lolium rigidum* 8 16 Echinochloa crus-galli* 6 15 Avena fatua* 6 16 Poa annua 6 15 Eleusine indica 5 5 Source: Heap (2000). These grasses have evolved resistance to many of the herbicides applied for their control *Infest hundreds of thousands of hectares worldwide. Table 2. Resistance to herbicides. II. Broad leaved weeds most resistant to herbicides Weed species Countries Chenopodium album 18 Amaranthus retroflexus 15 Conyza canadensis 14 Senecio vulgaris 12 Solanum nigrum 10 31

36 Narwal and Haouala Source: Source: Heap (2000). Farm Chemicals International Table 3. Resistance to herbicides. III. Amaranthus spp. resistant to herbicides Amaranthus Spp. Resistance to modes of actions A. retroflexus 3 A.hybridus 3 A.lividus 3 A. palmeri 3 A. powelli 2 A. rudus 2 A. albus 1 Source : Heap (2000) Crops have been grown since ancient times without damaging the environment but the use of herbicides during the short span of last 50 years has raised serious doubts about their continued use. Prior to invention of herbicides, weeds were controlled through mechanical and cultural practices. Allelopathy may help in weed control through inhibition of weed seed germination and seedling growth. Present understanding of the plant biochemistry, physiology, morphology, inter and intra-plant interactions and chemistry of natural products have shown that smothering crops, trap crops and allelochemicals may be used in weed control, overcoming the problems associated with herbicides. Rice (1995) suggested three allelopathic strategies for weed control (a) selection of weed smothering crops and breeding their varieties to control major weeds in a given area, (b) inclusion of allelopathic crops in rotation and/or use their residues as mulches (Liebman and Dyck, 1993) and (c) selecting allelochemicals from plants or microbes with herbicidal activity (Elakovich, 1989). This review outlines (a) and (b) strategies and the researches done at Haryana Agricultural University, Hisar, India. 2. SMOTHERING CROPS In crops, the smothering effect of one plant on another is mainly due to interference i.e. competitive and allelopathic interactions between the plant species. In agroecosystems, the competition for growth resources (sunlight, soil moisture, plant nutrients) and space starts few days after the emergence of the seedlings and becomes intense with time. The competition may be inter-species and/or intra-species. The later one, generally occurs in pure crops, while former occurs between different plant species e.g. between the component crops in mixtures/inter-cropping systems and or between the 32

37 Allelopathic strategies for ecological weed management crops and weeds or between the plants of the same crop sown in narrow rows or at higher plant density. The crop competition may not provide complete weed control but minimizes the weed growth and density through the smothering effect. While on the other hand, allelopathy exerts considerable inhibitory effect on the germination and growth of weeds (Weston, 1996). Hence, the combination of competitive and allelopathic effects (interference) may considerably reduce the weed density and growth. The interfering ability of crops may be harnessed for weed control through selecting weed smothering crops and breeding their weed smothering varieties. Table 4. Crops studied for weed management S.No. Crop S.No. Crop 1. Barley 11. Stizolobum spp 2. Rye 12. Heracleum spp 3. Wheat 13. Cassia spp 4. Sorghum 14. Sunflower 5. Pearl millet 15. Brassica spp 6. Maize 16. Sweet potato 7. Alfalfa 17. Squash 8. Sunn hemp 18. Tomato 9. Pigeon pea 19. Miscellaneous crops 10. Velvet bean 20. Table 5. Weed control potential* of crops Grading Summer crops Winter crops I Sorghum Rye II Alfalfa Barley III Velvet bean Sweet potato IV Brassica spp. V VI Sunflower Wheat Source : Narwal and Tauro (1996) *About 40 crop spp. possess weed control potential. Grading is based on the quantum of research done. Weed scientists have identified smothering crops that provide acceptable weed management in a crop production system and could possibly solve many problems associated with current practices of weed control. Tall growing crops having maximum growth rate exert greatest smothering effect 33

38 Narwal and Haouala on weeds, owing to their ability to out grow the weeds, intercept the incoming radiation, release inhibitory allelochemicals in the environment etc. Therefore, fast growing crops with a thick canopy cause maximum weed suppression. Barley, rye, maize, sorghum, sudangrass, buckwheat, proso millet, sunflower, rapeseed, soybean, hemp, sweet clover, alfalfa and cowpea effectively smother various weeds (Robbins et al., 1982) (Tables 4,5). Of these, barley, rye, sorghum, sudangrass, buckwheat, sunflower and sweet clover are generally sown to suppress weeds. Maximum weed suppression potential exists in multicut fodder crops or pasture spp. viz., sorghum, sudangrass, alfalfa and clovers etc., because their frequent cuttings/ grazing prevents or minimizes seed production and growth in weeds. The smothering effect of barley, rye, sorghum, wheat, alfalfa, clovers, vetches, Brassica spp., Heracleum, linseed, radish, sunflower and sweet potato, however has been attributed to allelopathic interactions. 3. BREEDING FOR WEED SMOTHERING VARIETIES Presently the ideal smothering crops does not exist; hence, new smothering plants must be bred for that specific purpose. Little research has been done in this regard. However, by combining weed science, biotechnology and plant breeding, it may be possible to develop "smother plants" that effectively suppress weeds and reduce use of herbicide. For example, a new smother plant was developed by crossing a dwarf Brassica campestris with B. campestris spp. perkinensis (Haan et al., 1994). These dwarf Brassica lines when sown between the maize and soybean rows germinated well and smothered the weeds for 4-6 weeks and did not influence the crop development. Hence, newly bred smother crops are a realistic option for weed management in cropping systems. Crop interference with weeds is one of the primary non-chemical method of weed control. Several major crop species have variability in traits that could be explored to develop varieties that interfere more with the weeds (Callaway, 1990). This is the appropriate time for plant breeders and crop-weed ecologists to develop crop varieties with enhanced interference capabilities with weeds. Superior weed suppressing genotypes have been reported in cucumber (Putnam and Duke, 1974), oat (Fay and Duke, 1977), rice (Dilay, 1992), sunflower (Leather, 1983b), soybean (Massantini et al., 1977), pearlmillet (Narwal et al., 1992), and Brassica (Sarmah et al., 1992) (Table 6). Putnam and Duke (1974) reported that wild types of existing crops possessed high allelopathic potential and that this character has been lost in the breeding of crop varieties for other characteristic viz., high yield etc. Although insect and disease resistance has been incorporated into the crop varieties through crossing with wild types but only one such effort has been made to develop crops with higher allelopathic potential to smother the 34

39 Allelopathic strategies for ecological weed management weeds, even though the character exists in the wild types. Rice is the only crop, in which breakthrough has been made to identify weeds smothering accessions and in the near future its transgenic lines with ability to control weeds may become available. Table 6. Phytotoxic crop varieties Crop Genotype Reference Rice Several Dilday et al. (1992) Cucumber PI Putnam and Duke (1974) Oat PI Fay and Duke (1977) Pearlmillet HHB 67, A x Narwal et al. (1992) Brassica juncea H 8689 Sarmah et al. (1992) B. napus HNS 8902 Sarmah et al. (1992) B. carinata BCCN 5 Sarmah et al. (1992) Soybean ND Massantini et al. (1977) Sunflower ND Leather (1983) Sunflower ND De Frank and Putnam (1977) Forney et al. (1985) Einhellig and Leather (1988), Sarmah (1992) Sweet potato ND Harrison and Peterson (1986) Narwal (1994a). Allelopathy in Crop Production, ND = Not determined, 3.1. Rice Dilday (1992) reported that 347 accessions out of 16,134 from 99 countries showed allelopathic activity against five aquatic weeds viz., ducksalad, signalgrass, redstem flatsedge and barnyard grass. Some of the accessions repelled weeds and maintained weed free area within a radius of cm around their base. Since rice is planted in rows spacing of cm, therefore, allelopathic activity would overlap the space between the rice plants or rows. Breeding for allelopathic traits has shown promise, the success has been achieved upto the third generation with continued research. Dilday et al. (1992) further reported that out of the tested accessions, 347, 161 and 6 accessions demonstrated allelopathic activity to ducksalad, purple ammania and broad leaf signal grass weeds, respectively (Table 7). Some accessions from India and Bangladesh exhibited allelopathic activity against 35

40 Narwal and Haouala barnyard grass and Cyperus iria. Fujii (1992) studied root exudates of 189 rice strains from the world over for the suppression effect on weeds in Plant Box method using lettuce as acceptor test spp. Improved cultivars of Japonica rice showed little allelopathic activity, while native varieties of Javanica type and red rice strains showed strong inhibitory activity. Park (1996) evaluated 38 allelopathic rice germplasm against 8 weed spp. (barnyard grass, Monchoria vaginalis, Persicaria hydropiper, Eleocharis kurguwai, Bidens tripartita, Cyperus serotinus, Alopecurus equalis and Leersia japonica) for their control. Three accessions viz., 'Tona brea 439', 'CICA4' and 'Tong gan' provided 62-70% weed control over the nonallelopathic variety 'Hwasungbyeo. Wang and Olofsdotter (1996) studied the growth pattern of allelopathic and non-allelopathic varieties. The former had higher shoot: root ratio based on dry weight than in later ones. The allelopathic rice variety had higher root efficiency, either due to higher nutrient efficiency or allelochemicals released from their roots affect the nutrient availability. These studies indicate that there are no extra physiological costs for allelopathic ability in the allelopathic cultivars. Keeping in view the great scope for breeding allelopathic rice varieties for weed control, International Rice Research Institute, Philippines, organised 'Rice Allelopathy Workshop' from November 24-26, 1996 (IIRI, 1996). This section describes the results presented from USA, Egypt, Korea and Philippines in this meeting. Dilday et al. (1996) reported that in field tests from , 412 rice accessions were identified having an area of allelopathic activity < 10 cm to ducksalad (Heteranthera limosa (sw) (Wild) and 155 accessions with the same allelopathic area to red stem (Purple ammania). The accessions allelopathic to ducksalad originated in 31 countries showing that allelopathic activity is multigenic. The hybrids between allelopathic x non-allelopathic lines gave higher yields and effectively controlled weeds. In Egypt, Hassan et al. (98) reported that out of 1000 accessions, 30 and 10 varieties suppressed Echinochloa crus-galli (50-90%) and Cyperus diffusa (50-75%), respectively. These varieties exhibited allelopathic activity at 3-4 leaf stage and inhibited root and emergence of first and second leaf in both weed spp. Kim and Shin (1996) in Korea, screened 92 rice accessions against E. crus-galli, seven varieties controlled the weed (35-75%) by reducing root growth of weed. In Philippines, Olofsdotter and Novarez (1996) reported that out of 111 rice cultivars, 13 suppressed the growth of Trianthema portulacastrum dry matter (40-50%) and 10 suppressed barnyard grass. These varieties did not effect the weeds population but suppressed their growth. Mattice et al. (1996) identified the allelochemicals released by rice under flooded and upland conditions. In flooded conditions, allelochemicals released were: 3- hydroxybenzoic acid (3-HBA), 3,4-dihydrocyhydiscinnamic acid (3-4-D HHCA) and 4-36

41 Allelopathic strategies for ecological weed management hydroxyphenylacetic acid from PI relative to Rexmont (nonallelopathic variety). While under upland conditions, allelochemicals were released in large quantity and were: 4- hydroxybenzaldehyde (4-HB),4-HBA, 3-hydroxy,4-methoxybenzoic acid (3-H, 4-MBA), 4-hydroxy cinnamic acid (4-HOA) in PI relative to Rexmont or blank soil. Perhaps these allelochemicals possess herbicidal activity. Table 7. Rice germplasm accession with potential allelopathic activity to broadleaf signalgrass, ducksalad and purple amannia ( ). Weed Germplasm designation Country of origin Radius of activity (cm) Weed control (%) Brod leaf Daudzai Pakistan Signal IR Philippines Grass UNMD Indonesia MGVR RICCU 132 Japan Ducksalad India AC 1423 India Tono Brea 439 Dominican Rep Tsai Yuan Taiwan Chon Donduni kunluz Afganistan Purple IR Philippines Ammania Cuba 65V58 USA Cuba 6558A USA IR Philippines IR Philippines Source: Dilday et al (1992). Check cultivars (Rexmont and Palmyra) had zero allelopathic activity. Moody (1995) reported that phytotoxic potential of crop residues could be exploited in weeds management. Soil incorporation of allelopathic rice germplasm straw controlled Cyperus iria L. almost similar to herbicide control (Lin et al., 1992). Khan and Vaishya (1996) reported that residues of rice 'sarjoo- 52' incorporated 5-6 cm deep at 5 t/ha reduced population and biomass of Echinochloa colonum (L.) (Link) and broad leaved weeds (Ammania bacifera L., A. multiflora Roxb. and Phyllanthus fraternus Webster). Narwal (1996) reported that inclusion of weed smothering crops 37

42 Narwal and Haouala like pearlmi1let, sorghum, Egyptian clover and oat in rice rotation may considerably decrease the weed population. 4. ALLELOCHEMICALS AS HERBICIDES Allelochemicals offer excellent potential as herbicides (Table 8). Firstly, they could be used directly as herbicides because these are free from all the problems associated with present herbicides. Secondly, their chemistry may be used to develop new herbicides (Table 9). As traditional methods of discovering and developing new herbicides have become more difficult and expensive, the interest in natural products as sources of herbicide chemistry has increased. Besides, public awareness and demand for environmentally safer herbicides with less persistence, more specific targets and less potential for contaminating groundwater makes searches for new weed control strategies, using natural products more attractive. Plants and microorganisms produce hundreds of secondary compounds (Table 10). Many of these compounds are phytotoxic and have potential as herbicides or as templates for new herbicide classes. It has been estimated that only about 3% of possible 400,000 secondary metabolites from plant and microorganisms have been so far isolated and identified. Only a fraction of those identified have been evaluated for herbicidal or bioregulator activity [Dodge (1987), Einhellig and Leather, (1988)]. This topic has been reviewed recently [Nair et al. (1990), Narwal and Tauro, (1994)]. hence, not discussed further. Table 8. Natural herbicides Herbicides (source) Weed spp. affected References Juglone (walnut) Redroot pigweed Weston et al (1989) Caffeine (coffee) Amaranthus spinosus Rizvi, et al. (1981) Strigol (cotton) Striga asiastica, Orobanche minor Spelce and Muselman (1981) Besides Dhurrin (Sorghum), gallic acid (spurge), floridzin (Apple), trimethylxanthene (coffee) and cinch (eucaptus) and some microbial toxins (anisomycin, tentoxin, bipoloroxin, hebimycidin) have also shown herbicidal activity. 38

43 Allelopathic strategies for ecological weed management Table 9. Allelochemicals based herbicides Natural product Source Herbicide Manufacturer PLANTS PRODUCTS Cineole Several plants Cinmethylin Shell USA Benzoxaziones (Hydroxamic acids) Graminae plants Benzanin BASF, Germany Quinolinic acid Tobacco plants Quinclorae BASF, Germany MICROBIAL PRODUCTS Anisomysin Streptomyces Methoxyphenone Nihon, Japan sp. Irpexil Iprex Benzodox Gulf, USA pachyton Fusaric acid Fusarium sp. Picloram Dow, USA n Monliformin Phosphinothrici Fusarium monliforme Streptomyces viridochromogenes Source: Hatzios (1987). 3,4-dibutoxymoniliformin Glutosonate CIBA- GEIGY, Switzerland Hoechst, AG, Germany 5. WEEDS MANAGEMENT RESEARCH IN INDIA We have conducted research on some of the smothering crops to manage the weeds at Haryana Agricultural University, Hisar, India. The smother crops suppress the weeds through interference, i.e. competition and allelopathy. In these fields studies, competition was minimized through adequate supply of soil nutrients as fertilizers and soil moisture through irrigation Summer weeds In India summer extends from April to October including the main rainy season (July-September). During this period availability of Photosynthetically Active Radiation and soil moisture (during rainy season) is maximum, these coupled with warm temperatures provides, most ideal conditions for weed growth. Two field studies described below were conducted for weed suppression through crops. 39

44 Narwal and Haouala Sorghum and pearl millet This study was conducted in the summer of 1990 and 1991 to determine (a) the effects of wheat residues management on the germination and growth of weeds and (b) the smothering effect of crops on the associated weed spp. It consisted of both field and laboratory studies. The field trial was conducted in split-plot Design with four replications. The wheat straw management treatments (removed, burnt, soil incorporated) were in the main plot and summer crops (fallow, sorghum, pearlmillet, maize, clusterbean and cowpea) in sub-plots. The mean temperature during the crop seasons varied between 30.5 to 33.6 C Field study: In both years, the straw management treatments stimulated the germination of weed seeds, while growing of forage crops decreased the weeds population. The residual effect of straw management and crops also persisted in the next crop season. The higher weed population in 1991 than in 1990 was due to rainfall immediately after the crop emergence, which favoured quicker germination of weed seeds (Narwal and Sarmah, 1996). (i) Broad leaved weeds: Among the broad leaved weeds, carpet weed is a major weed. It constitutes upto 70% population of broad leaved weeds and upto 50-60% of the total weeds. The straw burning or its incorporation increased the population of carpet weed from 2.6 to 8.4% and 37.7 to 41.9% and of total broad leaved weeds from % and 36.2 to 67.6%, respectively, as compared to straw removal. In bioassays, the aqueous extracts of wheat straw and wheat field soil also stimulated the germination of carpet weed over the control. The weed population data at fodder crops' harvest (70 DAS), showed that all crops suppressed the weeds over the fallow, but varied in their degree of suppression. Pearlmillet proved to be the most smothering crop and suppressed the population of carpet weed upto 80.8 to 85.80% and of broad leaved weeds upto 79.3 to 91.2% over the fallow (Table 11). The broad leaved weeds suppression followed the order: pearlmillet > maize > sorghum > clusterbean > cowpea. Table 10. Inhibitory/stimulatory effects of wheat straw management and Treatment crops on summer weeds density and dry matter. Trianthema portulacastrum weed Weed population broad grasses total Weed dry matter Straw management [%stimulation (+) over control (straw removal)] Burnt

45 Allelopathic strategies for ecological weed management Soil incorporated [% Inhibition (-) over control (fallow)] Sorghum Pearl millet Maize Clusterbeans Cowpea (ii) Grassy weeds: Similar to broad leaved weeds, the burning or soil incorporation of wheat straw increased the population of grassy weeds (Table 11). However, the degree of stimulation was greater in these weeds as compared to broad leaved weeds. The straw burning or its soil incorporation increased the grassy weeds population from 110 to 225% and 152 to 238%, respectively, over the straw removal. The straw and wheat soil extracts also stimulated the germination of grassy weeds at lower concentrations. Like the broad leaved weeds, the fodder crops differed in suppression of grassy weeds. Pearlmillet caused maximum suppression (83.7 to 100%) in grassy weeds, followed by sorghum (78.2 to 96.4%). The cereal fodders exerted greater smothering effect than legumes. (iii) Total weeds: Similar to broad leaved and grassy weeds the straw burning or soil incorporation increased the total weed population over the straw removal (Table 10). The straw burning and soil incorporation of straw increased the weed population by 20.4 to 60.1% and 49.5 and 84.8%, respectively, over its removal. The soil incorporation of straw increased the weed population perhaps, because allelochemicals released from the decomposing straw stimulated the weed seed germination as observed in the bioassays. The burning breaks the dormancy of weed seeds and thus increases their germination. Pearl millet proved to be the most smothering crop and suppressed the weed population upto 80.7% to 94.0% as compared to fallow. The greater weed suppression from pearl millet may be due to its faster growth rate, hence, competed well with weeds and its root exudates may contain certain allelochemicals which might have inhibited the weed seeds germination and seedling growth. Narwal et al. (1992) also reported the smothering ability of pearl millet genotypes for weed suppression. The sunlight interception studies through the test crops canopies showed that more PAR (Photosynthetically active radiation) reaches the soil surface in pearl millet crop than in maize, clusterbean and cowpea, even then the pearl millet smothers the weeds (Sarmah, 1992). This indicates the role of pearl millet allelopathy in weed suppression. 41

46 Narwal and Haouala The cereal fodders caused greater suppression of weeds than the legumes, owing to taller plants, which offered competition for light, soil moisture, nutrients and space. Besides, allelochemicals in root exudates may also be inhibitory to germination and early seedling growth of weeds. (iv) Weeds dry matter: Similar to weed population, the straw treatments also increased the dry matter accumulation in weeds. The straw burning or soil incorporation increased the dry matter production by 7.3 to 20.7% and 27.1 to 28.7% respectively than the straw removal. In bioassays, the wheat straw and soil extracts also increased the seedling growth (shoot and root length and dry matter) of all the test weed species. The fodder crops decreased the dry matter accumulation in weeds over the fallow. The cereal fodders caused greater reduction in dry matter than the legume fodders. Among the cereals, pearlmillet resulted in maximum reduction of 88.8% to 96.1% in the dry matter production of weeds. (v) Residual effects: In undisturbed plots and sorghum crop, the residual effect of straw management treatments and preceding fodder crops persisted upto days after harvest (DAH) of fodder 'crops, respectively. The straw management treatments increased the weed population, similar to the results of the original experiment. Similar to wheat straw, perhaps allelochemicals exuded as root exudates in soil by previous fodder crops continued to suppress the weeds, like the preceding crops. Pearlmillet caused maximum suppression (54 to 67.6%) over the fallow, probably due to release of some phytotoxins from its decomposing stubbles Bioassays (i) Wheat straw: The wheat straw extract had variable effect on the germination and seedling growth of test weed spp. (Table 10). It stimulated the germination in carpet weed, barnyard grass and crowfoot grass but inhibited that of pigweed and sunberry. Except in carpetweed, the germination in all test weed spp. was inhibited at higher concentration (10%) of extract. The degree of inhibition was greater in sunberry and pigweed. The extracts stimulated all the seedling growth parameters viz., root and shoot length and dry matter in broad leaved weeds except in sunberry. At lower concentrations (5%), seedling growth of all spp. was increased except in sunberry. However, higher concentration of extract, proved inhibitory to grassy weeds (Barnyard grass and crowfoot grass) and sunberry. In sunberry, wheat extract inhibited the germination and seedling growth and perhaps that is the reason of its less infestation in wheat based rotations. 42

47 Allelopathic strategies for ecological weed management The extracts stimulated the germination and seedling growth of carpet weed and pigweed and that may be the reason for their greater infestation in the subsequent crops following wheat. (ii) Wheat soil: The soil extracts stimulated the germination of carpetweed and crowfoot grass over the control, while it inhibited the germination of pigweed, sunberry and barnyard grass. It proved less inhibitory to germination and seedling growth of weeds than the wheat straw extract, perhaps, owing to lower concentration of water extractable chemicals in,oil than in wheat straw. The organic acids like ferulic, coumaric, cinnamic, vanillic, benzoic, hydroxamic acids etc. are present in wheat residues. These are stimulatory at lower concentrations and inhibitory at higher concentrations [Thorne et al. (1990), Young et al., (1989)]. The crop residues (roots and stubbles) left in the field after crop harvest are sources of phenolic compounds in soil (26). Waller et al. (1987) also reported inhibitory effect of wheat soil extract and the sources of phytotoxic substances in rhizosphere soil were root exudates or microbial toxins. The seedling growth of all test weed spp. was stimulated by the soil extract except in sunberry at higher concentration (50%). The maximum stimulation in shoot length occurred in carpet weed and crowfoot grass and minimum in sunberry. While maximum root elongation was observed in grassy weeds and minimal in sunberry. The dry matter accumulation was greater in pigweed and crow foot grass and minimal in barnyard grass PEARL MILLET GENOTYPES The maximum smothering effect of pearl millet on weeds as compared to other summer crops (Narwal and Sarmah, 1996) encouraged the Author to screen pearl millet genotypes for weed suppression on the pattern of earlier studies with cucumber (Putnam et al., 1983), oat (Fay and Duke, 1977), sunflower (Leather, 1987) and soybean (Madeiros, 1990). A field trial was conducted to determine the smothering capability of 13 accessions of pearl millet (Pennisetum typhoides L.) on weeds. Since the field was highly infested with weeds, the studies were conducted with natural weed seed bank in the field. At pearl millet harvest, the weed population and dry weight were recorded. Two most dominant weed spp. (Trianthema portulacestrum L. and Amaranthus spinosa L.) were recorded separately. While other species like Cyperus rotundus and Physalis minima were present in some plots. All the pearl millet genotypes reduced the weed population of Trianthema portulacastrum, Amaranthus spp. and total weeds, compared with control. Nine genotypes significantly smothered the total weed population over the control. Of these, HHB 67, ranked first in weed suppression (72.3%) over the control, closely followed by 88004A x (71.1%), HHB 60 (57.5%) and 863A x HTP 88/33 (57.2%) (Table 11). Other 43

48 Narwal and Haouala genotypes suppressing 50% weed population over control were 88006A x 90/4-5 (54.6%) and 843Ax HTP 88/47 (53.5%). Four genotypes viz., 843A x HTP 88/47, 81A x HC4, 88006A x and 861A x 77/273 suppressed the weed > 40% over the control. Weed population of Trianthema portulacastrum varied greatly with different genotypes of pearlmillet, while genotypes HHB 67 sufficiently suppressed its population (74.8%) over the control closely followed by 88004A x (72.6%). Smothering of this weed species by other genotypes such as HHB 60 (57.3%), 843A x mp 88/33 (56.7%), 8806A x 90/4-5 (55.7%) and 843A x mp 88/47 (55.4%) was quite satisfactory. The pearlmillet cultivars viz., HHB 50, HHB 60, 81A x HC-4, 843A x HTP 88/33 and 843A x HTP 88/47 significantly suppressed the Amaranthus population over the control and these cultivars had similar suppression effect. Shetty and Rao (2006) also reported that sole pearlmillet suppressed the growth of weeds much more strongly than sole groundnut. Table 11. Suppression effects of pearl millet accessions on the population of summer weeds/m 2. % suppression of weed population over control (fallow) Accession Chenopodium Total weeds album L. HHB A x HHB A x HTP 88/ A x 90/ A x HT 8 88/ A x HC A x A x 77/ HHB A x A x 77/ HHB All pearl millet genotypes significantly reduced the dry matter of weeds as compared to the control. The variety HHB 67 and the genotype 88004A x caused maximum suppression of 87.7 and 85%, respectively over the control. The pearl millet genotypes did not significantly differ in their plant population, plant height and fodder yields. Hence, the differences 44

49 Allelopathic strategies for ecological weed management in the weed populations in different genotypes, indicate the variability in suppression effect of the genotypes Winter weeds In India winter (November to March) is generally dry, hence, weeds are a major problem in irrigated agriculture; while in rainfed areas they compete with crops for conserved soil moisture. The heavy weed infestation in the later case may result in crop failure due to depletion of soil moisture by weeds. In irrigated areas, herbicides are used extensively, which has resulted in development of resistance in Phalaris minor to isoproturon herbicide only in rice-wheat rotation. Perhaps because maximum herbicides are used in ricewheat rotation as it produces maximum food grains ( t/ha) and both these crops are Graminae. It is likely that in the near future, many weed spp. may develop such resistance. World over several weed spp. have become resistant to various herbicides, hence, it is a burning problem for the weed scientists. This has necessitated more research on allelopathy, to overcome such problems. Two studies were conducted with Brassica spp. and rice straw BRASSICA SPP. ACCESSIONS These are major oilseed crops of winter and are grown over large areas. Oleszek et al. (1992) in their review concluded that some Crucifereae spp. possess potential to inhibit germination and growth of weeds and thus these spp. could be successfully used in weed control. The degradation products of glucosinolates seems to be responsible for allelopathic potential of Brassica spp. The field studies were conducted to determine the smothering effect of three Brassica spp. viz., B. juncea, B. napus and B. carinata accession on the weed spp. The crops were sown in completely randomized design with three replications in plots of 6 x 4 m. The crops were raised with the recommended cultural practices and uniform plant stand was maintained, however, no herbicide or cultural practices were applied for weed control. The weed population and dry weight were recorded at crop harvest. The genus Brassica is reported to have allelopathic properties that can affect germination, establishment and growth of other species in agroecosystems [Jimenez osorino (1987), Lovett and Duffield, (1981)]. Broccoli also showed a potential for allelopathic interference on weeds depending upon the growth stage (Jimenez-Osorino and Gliessman, 1987). Wild mustard has a complex reaction on the crop environment and controls weeds and pests. The complex of glucosinolates and their derivatives common to the genus Brassica are being explored as possible active agents for the control of both weeds and pests. 45

50 Narwal and Haouala Brassica juncea: The genotypes successfully smothered the population of all weeds species. Significantly lower weed population and weed dry matter were recorded in all the genotypes over no crop control and per cent suppression was greater in dicot the in monocot weeds. The genotypes successfully smothered the population of all weeds species. Among the genotypes, RH 8689 showed maximum ability to smother the weed population (8.3 weeds/m 2 ), followed by RH 8605 (13.09 weeds/ m 2 and RH 8693 (18.1 weeds/m 2 causing 91.6, 85.9 and 81.4% suppression, respectively, over the control (98.4 weeds/m 2 ), however, the genotype Varuna had the least smothering effect (Table 12). Weed population suppression in other accessions were identical with 61.5 to 81.3% reduction over the control. All the genotypes significantly decreased (> 80%) C. album population compared with no crop control. Although all genotypes significantly decreased the population of P. minor, but most potent genotypes were RH 8689 (2.5 weeds/m 2 ). Table 12. Suppression effects of Brassica juncea accessions on population and dry matter of winter weeds/m 2. % suppression of weed population Accession over control (fallow) Total weeds Phalaris minor L. RH (78.0)* 87.9 RH (78.7)* 80.7 RH (76.8)* 71.3 RH (82.0)* 68.2 RH (77.7)* 62.1 RH (77.2)* 51.8 All accesionsr educed the Chenopodium album population by 80%, * % suppression of dry matter RH 8693 (4.0 weeds/m 2 ) and RH 8814 (4.5 weeds/m 2 ) with 87.9, 80.7 and 71.3% reduction, respectively, over the control. Lovett and Duffield (1981) and Jimenez Osomio (1984) also observed that some species of the Brassicae family considerably affected germination, establishment and growth of other species. The genotypes had no significant effect on Cyperus spp. compared with the control. Dry matter production in weeds was also significantly lower in all the genotypes over the control. Among the genotypes, RH 8113 recorded the lowest dry matter production (6.8 g/ m 2 closely followed by RH 8605 (8.0 g/m 2 and RH 8689 (8.3 g/m 2 ), RH 8812 (8.4 g/m1 and RH 8602 (8.6 g/m 2 ) showing 82.0, 78.7, 78.0, 77.7 and 77.2% 46

51 Allelopathic strategies for ecological weed management reduction, respectively, over the control. Weed dry matter in all other genotypes was at par. In later studies during (Rice, 1995), out of 40 accessions RH 8539, RH 8546, RH 8686, RH 9689, RH 8690, RH 8693 and RH 8696 decreased the weed population by 76.7 to 87.1% over the control, respectively Brassica napus: All the genotypes significantly reduced the population and dry matter of weed species over the no crop control (Table 13). Among the genotypes HNS 8902 showed the maximum suppression of weeds population (19.3 weeds/m 2 ) closely followed by N (22.0 weeds/m 2 and N (24.0 weeds/m 2 resulting in 61.3, 56.0 and 52.0% reduction, respectively, over the control (50.0 weeds/m 2 ). The population of the dominant weed C. album was suppressed by genotypes N (50.0%), Tower 5-2 (47.8%), N (47.8%), HNS 8902 (45.7%), Tower 7A (37.0%), N (32.6%), and Tower (28.3%) over the control. The genotypes, however, showed a variable response to Convolvulus arvensis. Two of them (HNS 11-1 and N ), completely suppressed the weeds, while four genotypes (N , N , Midas and Tower 6-1-3) increased its population. In case of Cyperus spp. the genotype 'Midas' completely suppressed this weed and four others (N , N and check RH 8113) caused > 80% suppression over the control. However, in two genotypes viz., HNS 11-1 and Tower 5-2, its population was more than in the control. It was observed that with all the genotypes, dicot weed population exceeded the monocot weeds and majority of the genotypes caused greater suppression in the dicots than in the monocots. Leather (1983b) reported that tissue leachates of B. napus inhibited the growth of Abutilon theophasti and Ipomoea spp. but did not affect wild mustard. Weed dry matter production was least in genotypes HNS 8902 (5.87 g/m 2 ) closely followed by HNS 11-1 (9.4 g/m 2 ) with 83.8 and 74.1% reduction, respectively, over the control (36.3 g/m 2 ). Significantly lower weed dry matter was recorded in HNS 8902 as compared to 'Midas' (32.87 g/m 2 ). Yadav et al. (1994) screened 25 accessions for weed suppression and found that all genotypes reduced the weed population, but early maturing lines from Japan and Canada viz., N , N , N , N , Tower 5-2 and Tower 7A showed > 80% suppression in weed population as compared to control. Adverse effects of Brassica genus on establishment and growth of weed species had also been reported earlier [(Jimenez osorino (1984), Lovett and Duffield, (1981)]. 47

52 Narwal and Haouala Table 13. Suppression effects of Brassica napus accessions on population and dry matter of winter weeds/m 2. Accession [% suppression of weed population over control (fallow)] Total weeds Chenopodium album BCCN (65.8)* 50.9 BCCN (80.1)* 623 BCCN (50.5)* 56.3 BCCN (60.2)* 47.4 BCCN (66.0)* 54.7 BCCN (58.9)* 49.1 BCCN (35.2)* 66.0 Convolvulus arvensis: BCCN-3M BCCN-4, BCCN08 caused > 65% suppression in plant density * % suppression of weed dry matter Brassica carinata: Significantly lower weed population and dry matter were recorded in all the B. carinata genotypes over the control except BCCN-l (Table 14). Among the genotypes, BCCN-2 recorded the least weed population (10.66 weed/m 2 ) with 61.4% reduction over the control (27.67 weed/m 2 ). The smothering ability in other genotypes (BCCN-3, BCCN-8, BCCN-6 and BCCN-4) ranged from 32.6 to 44.6%. There was great variability in the weed population of Chenopodium album among the genotypes. More than 50% reduction of Chenopodium album population was recorded in three genotypes viz., BCCN-2 (66.0%), BCCN- 6 (54.7%) and BCCN-5 (50.9%). Inconsistency in the population of Convolvulus arvensis was observed among the genotypes of B. carinata. Five genotypes (BCCN-4, BCCN-5, BCCN-8, BCCN-3 and RH 30) recorded 65% reduction in population while in three genotypes (BCCN-l, BCCN-6 and BCCN-7), its population increased over the control. All the genotypes significantly reduced the weeds dry matter yield over the control. Genotypes BCCN-5 recorded the lowest dry matter production (6.33 g/m 2 ) followed by BCCN-8 (10.8 g/m 2 ) and BCCN-2 (10.87 g/m 2 ) showing 80.1, 66.0 and 65.8% reduction over control (31.8 g/m 2 ). Other genotypes causing 50% reduction in weed dry matter were BCCN-3 (60.2%), BCCN-6 (58.9%) and BCCN-1 (50.5%). Weed dry matter in all the genotypes was at par except that BCCN-5 significantly differed with BCCN-4 (20.6 g/m 2 (35.2% weeds suppression). In further studies during , 20 accessions were assessed for weeds smothering effect. The genotypes HC2, Car 6A, C6Y S7B, HC 9003, HC 9014, HC 9015 and HC 9016 decreased the weeds density by 44.6 to 65.6% over the control. Adverse effect of the Brassicae family on germination, establishment and growth of other species has been reported earlier [Leather (1983b), Lovett and Duffield, (1981)]. 48

53 Allelopathic strategies for ecological weed management Table 14. Suppression effects of Brassica carinata accessions on population and dry matter of winter weeds species/m 2. Accession [% suppression of weed population over control (fallow)] Total weeds Chenopodium album HNS (83.8)* 45.7 N (33.7)* 47.8 N Tower Tower 7-A N Tower Convolvulus arvensis: HNS 11-1 and N completed suppressed the weed. Cyperus spp: Midas caused complete suppression and N , N resulted in > 80% suppression. * % suppression of weeds dry matter Oat and berseem (Trifolium alexandrinum L.) Pot Study: The study was done in pots in an open air net house during the winter of , to determine (a) the suppression effect of crops on weeds and (b) influence of soil incorporation of rice straw on weeds. The experiment was conducted in the soil brought from a rice field in the paddy growing belt, Village Pabnawa, District Kaithal, Haryana, India. The rice straw, stubbles and soil (upper 15 cm layer) were collected after the harvest of summer rice crop in November, The soil was sieved through 2 mm sieve to remove crop and weed residues. It was filled in pots (30 cm height, 20 cm 5.0 kg soil/pot. As per main treatments, rice stubble and stubbles + straw were mixed in the top 15 cm soil in the pots, in the same proportion as found in the field i.e. 1.1 g stubbles (2.2 t/ha) and 2.6 g stubble + straw/kg soil (5.2 t/ha). Thereafter, pre-sowing irrigation was provided. The sub-treatments consisted, of rice residue management (control, stubble, stubble + straw incorporated in soil) and field crops [wheat 'HD 2329, oat OS6 berseem 'Muscavi', lentil 'L9-12' and fallow). The treatments were replicated 11 times in completely randomized design. The crops were raised with recommended cultural practices except weed control. The soil incorporation of rice residues, suppressed the plant density of weeds, however, test crops exhibited both inhibition or stimulation and decreased the weed biomass. 49

54 Narwal and Haouala Broad leaved weeds: Soil incorporation of rice stubbles or stubbles + straw decreased the weed density over the control (Table 15). The suppression of weed population was greater in the earlier stages i.e. at 15 DAS (days after sowing) and decreased in the later stages (45 DAS). Perhaps, the phytotoxicity of decomposing rice residues decreased 15 days after soil incorporation. The test crops had variable effect on the weed density. Wheat and berseem decreased the weed population, whereas oat and lentil increased it. Perhaps, the root exudates of later crops stimulated the germination of weeds. Berseem proved to be the most smothering crop to the broad leaved weeds and caused 52.93% suppression as compared to wheat (16.76%). Oat caused slightly greater suppression in grassy weed population than lentil only at 15 DAS. In contrast to the plant population of weeds, both soil incorporated rice residues and test crops considerably decreased the dry biomass of weeds as compared to the control (Table 10). Soil incorporated rice stubbles caused greater suppression in weed dry matter than stubbles + straw. The inhibitory effects of decomposing crop residues on the growth of many weed spp. have already been reported [Guenzi and McCalla, (1966), Guenzi et al (1967), Leather (1983a), Purvis et al. (1985), Putnam and DeFrank (1979), Putnam and Duke (1974)]. Kuwatsuka and Shindo (1973) Table 15. Effects of rice residues and test crops on the winter weeds population/pot. Treatment Broad leaved weeds Grassy weeds 15* 30* 45* 15* 30* 45* [% inhibition (-)/stimulation (+) over control (fallow)] Soil incorporated rice residues Stubles Stubles straw Test Crops Wheat Oat Berseem Lentil isolated 13 phenolic acids in rice straw and its decayed products. The effect of suppression 50

55 Allelopathic strategies for ecological weed management increased up to 90 DAS and decreased afterwards. The toxicity of phenolic acids decreased with progress in decomposition (Guenzi et al.,(1967). The smothering effect of crops on weeds dry matter followed the order: berseem > oat > lentil > wheat (Table 11). The degree of suppression increased up to 120 DAS in crops. The suppression was maximum in berseem (87.5%), oat (75.4%), lentil (50.2%) and wheat (44.2%) as compared to fallow at 120 DAS. However, the interaction effect of soil incorporated rice stubbles further ameliorated the degree of weed dry matter suppression in berseem, oat, lentil and wheat to 88.9, 78.4, 54.3 and 54.6% respectively, over the fallow control. Altieri and Doll (1978), Leather (1983a), Rice (1984), Chou (1987) and Putnam (1988) have also observed and reported several crops which have the ability to suppress Grassy weeds: The effect of rice residues and test crops on grassy weeds was entirely different than on broad leaved weeds (Table 9). The soil incorporated rice stubbles or stubbles + straw suppressed the weed population upto 15 DAS and thereafter, improved it. The inhibitory effect was greater in stubbles + straw incorporation over the stubbles alone incorporation, but both had identical stimulatory effect. All the test crops suppressed weed density upto 15 DAS and increased afterwards till 45 DAS. Oat and wheat caused maximum increase in weed population. Both soil incorporated rice stubbles or stubbles + straw increased the dry mass of grassy weeds and the former proved superior than the later upto 120 DAS (Table 10). On the contrary, all the test crops proved inhibitory to grassy weeds. The smothering effect increased linearly upto 120 DAS. The smothering effect of crops at 120 DAS followed the order: berseem (90.0%) > lentil (84.0%) > oat (62.3%) > wheat (46.5%) BIOASSAYS The bioassays were conducted with the aqueous extracts of rice stubbles or stubbles + straw in 9 cm dia petri dishes in BOD Incubator at 20 C 2. The treatments were: Test weed spp. viz., Convolvulus arvensis L., Avena ludoviciana Dur, Phalaris minor Retz and Chenopodium album L. and aqueous extracts (control, stubble extract 5% and 10% and stubble + straw extract 5% and 10%). The treatments were replicated four times in Completely Randomized Design. The aqueous extracts of rice stubbles or stubbles + straw at both concentrations of 5 and 10% inhibited the germination and seedling growth of test weed spp. The variability in inhibitory effect of straw or straw + stubble was perhaps because the phenolics concentration varies among the plant parts (Guenzi et al., 1967). (I) Broad leaved weeds 51

56 Narwal and Haouala (i) Convolulus arvensis: The aqueous extracts of both rice stubbles or stubbles + straw and at both concentrations (5 and 10%) inhibited the germination and seedling growth of C. arvensis over the control (Table 12). The stubble + straw extract irrespective of concentrations was more inhibitory than stubble extract. This indicates that straw contains more inhibitory allelochemicals than the stubbles. The inhibition in germination and seedling, growth was concentration dependent i.e. higher concentrations (10%) were more inhibitory than lower concentrations (5%). The extracts had similar inhibitory effect on shoot length and dry weight but were more inhibitory to root elongation than the dry weight. (II). Grassy weeds The aqueous extracts of rice residues proved more inhibitory to both grassy weeds as compared to broad leaved weeds. (i) Avena ludoviciana: Similar to C. arvensis both extracts and their both concentrations were inhibitory to germination and seedling growth of A. ludoviciana and the inhibition was concentration dependent (Table 12). The stubble extract had identical inhibitory effect on shoot length and dry matter, however, stubble + straw extract was more inhibitory to shoot dry matter than its length. However, stubble or stubble + straw extracts caused more inhibition in root dry matter than its elongation. (ii). Phalaris minor: Like A. ludoviciana and C. arvensis both the extracts and their both concentrations were inhibitory to germination and seedling growth of P. minor and the inhibition was concentration dependent (Table 12). The extracts proved more inhibitory to shoot dry matter and elongation than the root. The stubble + straw extract at 10% caused complete (100%) inhibition in seedling growth. 6. PROSPECTS, CONCLUSIONS AND FUTURE LINES OF RESEARCH These studies have shown that allelopathic strategies including use of smothering crops could provide weed control, both in summer and winter crops. Although, these crops do not provide complete weed control but can manage weed population at economic threshold levels. This may either eliminate or minimize the use of present herbicides and thus overcome all the major problems associated with herbicides. These studies have shown the potential of weed control of summer and winter crops. The order of weed suppression in summer crops followed the order: pearlmillet > maize > sorghum > clusterbean > cowpea and the order in winter crops was: berseem > oat > lentil > wheat. The studies with accessions of pearlmillet and Brassica spp. (B. juncea, B. napus, B. carinata) exhibited greater variability in their weed smothering ability. 52

57 Allelopathic strategies for ecological weed management 7. FUTURE LINES OF RESEARCH To provide satisfactory weed control in field crops using allelopathic strategies, Narwal (1994) has suggested research on the following aspects of crop interference: (i) In the world about 500 domesticated plant spp. are grown as crops and these plants offer a great scope for selection of weed smothering spp. (ii) In the promising crops, their varieties may be screened for smothering potential. (iii) The genes responsible for production of smothering allelochemicals may be identified and possibly transferred to develop new transgenic varieties of same or other crops using techniques of biotechnology so that plants could produce their own herbicides. (iv) Research may be directed to utilize microbial and fungal toxins to control weeds. (v) New and cheaper synthetic analogues of natural products having greater selectivity, stability and efficacy to control weeds may be developed. (vi) The agronomical practices (sowing time, plant population, row spacing, crop geometry, crop mixture/intercropping) may be further improved to provide competitive edge to crops over weeds. vii) Crop rotations with allelopathic crops to control weeds may be developed. References AHRENS, J.F. (1989). Meeting the challenges. Weed Technology 3: ALTIERI, M.A. and DOLL, J.D. (1978). The potential of allelopathy as a tool for weed management. PANS 24: BORNER, J. (1960). Liberation of organic substances from higher plants and their role in soil sickness problem. Botanical Review 26: CALLAWAY, M.B. (1990). Crop Varietal Tolerance to Weeds: A Compilation. Publication Series No Ithaca. USA: Cornell University. CHOU, C.H. (1983). Allelopathy in agroecosystems. In: Allelochemicals and Pheromones (Eds., C.H. Chou and G.R. Waller). pp Taipei, Taiwan: Institute of Botany, Academia Sinica. CHOU, C.H. (1987). Allelopathy in subtropical vegetation and soils in Taiwan. In: Allelochemicals: Role in Agriculture and Forestry (Ed., G.R. Waller) ACS Symposium Series 330: Washington, D.C.: American Chemical Society. DEFRANK, J. and PUTNAM, A.R. (1977). Proceedings, North Central Weed Control Conference 32: DILDAY, R.H. (1992). Victims no one mourns. Agricultural Research 40(2): DILDAY, R.H., FRANS, R.E., SEMIDEY, N., SMITH, R.J. and OLIVER, L.R. (1992). Weed control with crop allelopathy. Arkansas Farm Research 41(4): DILDAY, R.H., YAN, W.G. and MOLDENHAUER, K.A.K. (1996). Allelopathic activity in rice to major aquatic weeds. Workshop on Rice Allelopathy. November 22-24, Philippines: International Rice Research Institute. 53

58 Narwal and Haouala DODGE, A.D. (1987). Potential new targets for herbicides. Pesticide Science 20: EINHELLIG, F.A. and LEATHER, G.R. (1988). Potentials for exploiting allelopathy to enhance crop production. Journal of Chemical Ecology 14: ELAKOVICH, S.D. (1989). Allelopathic aquatic plants for aquatic weed management. Biologia Plantarum 31: FAY, P.K. and DUKE, W.B. (1977). An assessment of allelopathic potential in Avena germplasm. Weed Science 25: F.A.O. (1990). Proc. FAO International Conference on Weed Control. Davis, California: University of California. F.A.O. (1997). Expert Consultation Group Meeting on Weed Ecology and Management. September 21-24, Food and Agricultural Organisation, Rome, Italy. FORNEY, R.D., ROY, C.L. and WOLF, D.D. (1985). Weed suppression in no-til alfalfa (Medicago sativa) by prior cropping of summer-annual forage grasses. Weed Science 33: FUJII, Y. (1992). The potential biological control of paddy weeds with allelopathy: Allelopathic effects of some rice varieties. Proceedings, Conference Biological Control and Integrated Management of Paddy and Aquatic Weeds in Asia. pp Tsukuba, Japan: National Agricultural Research Centre. GRESSEL, J. (1985). Herbicide tolerance and resistance: Alteration of site of activity. In: Weed Physiology Vol. 2. Herbicide Physiology (Ed., S.O. Duke). pp Boca Raton, FL, USA: CRC Press. GUENZI, W.D. and MCCALLA, T.M. (1966). Phenolic acids in oats, wheat, sorghum and corn residues and their phytotoxicity. Agronomy Journal 58: GUENZI, W.D., MCCALLA, T.M. and NORSTADT, F. (1967). Presence and persistence of phytotoxic substances in wheat, oat, corn and sorghum residues. Agronomy Journal 59: HAAN, R.L., WYSE, D.L., EHIKE, N.J., MAXWELL, B.D. and PUTNAM, D.H. (1994). Simulation of spring seeded smother plant for weed control in corn. Weed Science 42: HARRISON Jr., H.F. and PETERSON, J.K. (1986). Allelopathic effects of sweet potatoes (Ipomoea batatas) on yellow nutsedge (Cyperus esculentus) and alfalfa (Medicago sativa). Weed Science 34: HASSAN, S.M., AIDY, I.R., BASTAWISI, A.O. and DRAZ, A.E. (1996). Weed management in rice using allelopathic rice varieties in Egypt. Workshop on Rice Allelopathy, November 22-24, Philippines: International Rice Research Institute. HEAP, J. (2000). Farm Chemicals 14 (5): IRRI. (1996). Workshop on Rice Allelopathy. November 25-27, International Rice Research Institute, Los Banos, Philippines. JIMENEZ-OSORINO, J.J. (1984). Interactions in Wild Mustard and Broccoli Agroecosystems. M.A. Thesis, Santa Cruz, USA: University of California. KHAN, A.H. and VAISHAYA, R.D.(1992). Allelopathic effects of different crop residues on germination and growth of weeds. Proc. National Symposium Allelopathy in Agroecosystem (Ed., P. Tauro and S.S. Narwal). pp Hisar, India: Indian Society of Allelopathy, Haryana Agricultural University. KIM, K.U. and SHIN, D.H. (1996). Rice allelopathy research in Korea. Workshop on Rice Allelopathy. November 24-26, Philippines: International Rice Research Institute. LEATHER, G.R. (1983a). Weed control using allelopathic crop plants. Journal of chemical Ecology 9:

59 Allelopathic strategies for ecological weed management LEATHER, G.R. (1983b). Sunflowers (Helianthus annuus) are allelopathic to weeds. Weed Science 31: LEATHER, G.R. (1987). Weed control using allelopathic sunflower and herbicides. Plant and Soil 98: LIEBMAN, M. and DYCK, E. (1993). Crop rotation and intercropping strategies for weed management. Ecological Applications 3: LIN, J., SMITH, R.J. and DILDAY, R.H. (1992). Allelopathic activity of rice germplasm on weeds. In: Proceedings, 45th Annual Meeting, Southern Weed Science Society, Little Rock, Arkansas, USA. pp. 99. LOVETT, J.V. and DUFFIELD, A.M. (1981). Allelochemicals of Camelina sativa L. Journal of Applied Ecology 18: MASSANTINI, F., CAPORATI, F. and ZELLINI, F. (1977). In: Proceedings, European Weed Research Society (EWRS) Symposium on the Different Methods of Weed Control and their Integration 1: 23. MATTICE, J., LAVY, T. and SKULMAN, B. (1996). A search for allelochemicals in rice responsible for the control of ducksalad. Workshop on Rice Allelopathy. November 22-24, Philippines: International Rice Research Institute. MEDEIROS, A.R.M., CASTRO, L.A.S. and LUCHES, A.A. (1990). Annails Escola superior de Agri. Luizde Queroz 47(2): MOODY, K. (1995). Sustainability in rice weed management. In: Proceedings 15th Asia- Pacific Weed Science Congress. Tsukuba, Japan. pp MUDGE, L.L., GOSSETT, B.J. and MURPHY, J.R. (1984). Resistance of goose grass to dinitroaniline herbicides. Weed Science 32: NAIR, M.G., WHITENACK, C.J. and PUTNAM, A.R. (1990). 2,2'-oxo-1,1' azobenzene: A microbially transformed allelochemical from 2, 3-benzoxazolinome. Journal of Chemical Ecology 16: NARWAL, S.S. (1996). Allelopathic strategies for weed management in rice-wheat rotation for sustainable agriculture. Lecture delivered at Workshop on Rice Allelopathy, November 25-27, (1996). International Rice Research Institute, Los Banos, Philippines. NARWAL, S.S. (1997). Allelopathy and its practical use for weed management. Lecture delivered at Expert Consultation Group Meeting on Weeds Ecology and Management, September 21-24, Food and Agricultural Organisation, Rome, Italy. NARWAL, S.S. and SARMAH, M.K. (1996). Effect of wheat residues and forage crops on the germination and growth of weeds. Allelopathy Journal 3: NARWAL, S.S., SARMAH, M.K., DAHIVA, D.S. and KAPOOR, R.L. (1992). Smothering effect of pearlmillet genotypes on weed species. Proc. National Symposium Allelopathy in Agroecosystems. (Eds., P. Tauro and S.S. Narwal). pp Hisar, India: Indian Society of Allelopathy, Department of Agronomy, Haryana Agricultural University. NARWAL, S.S. and TAURO, P. (1994). Allelopathy in Agriculture and Forestry. Jodhpur: Scientific Publishers. 310 pp. OLESZEK, W., ASCARD, J. and JOHANSON, H. (1996). Brassicacae as alternative plants for weed control. In: Allelopathy in Pests Management for Sustainable Agriculture (Eds. S.S. Narwal and P. Tauro. pp Jodhpur, India: Scientific Publishers. OLOFSDOTTER, M. and NAVAREZ, D. (1996). Allelopathic rice for weed control. Workshop on Rice Allelopathy. November 22-24, Philippines, International Rice Research Institute. 55

60 Narwal and Haouala PARK, K.H. (1996). A potential weed management by allelopathic rice germplasm in Korea. In: Abstracts I World Congress on Allelopathy. Abstract No. H-16, pp Cadiz, Spain: International Allelopathy Society. PURVIS, C.E., JESSOP, R.S. and LOVETT, J.V. (1985). Selective regulation of germination and growth of annual weeds by crop residues. Weed Research 25: PUTNAM, A.R. (1988). Allelopathy: Problems and opportunities in weed management. In: Weed Management in Agroecosystems: Ecological Approaches (Eds., M.A. Altieri and M. Liebnam) pp Boca Raton, FL, USA: CRC Press. PUTNAM, A.R. and DEFRANK, J. (1979). Use of cover crops to inhibit weeds. Proceedings, IX International Congress of Plant Protection. pp PUTNAM, A.R. DEFRANK, J. and BARNES, J.P. (1983). Exploitation of allelopathy for weed control in annual and perennial cropping systems. Journal of Chemical Ecology 9: PUTNAM, AR. and DUKE, W.B. (1974). Biological suppression of weeds: Evidence for allelopathy in accessions of cucumber. Science 185: RAMAKUDZIBGA, A.M. (1991). Allelopathic effects of aqueous wheat (Triticum aetivum L.) straw extracts on the germination of eight arable weeds found in Zimbabwe. Zimbabwe Journal of Agricultural Research 29: RICE, E.L. (1984). Allelopathy. New York: Academic Press. 422 pp. 2nd ed. RICE, E.L. (1995). Biological Control of Weeds and Plant Diseases: Advances in Applied Allelopathy. Norman, USA: University of Oklahoma. 440 pp. ROBBINS, W., CRAFTS, A.S. and RAYNOR, R.N. (1982). Weed Control. New York: McGraw Hill. SARMAH, M.K. (1992). Allelopathic Effect of Wheat Residues on the Succeeding Crops and Weeds. Doctoral Dissertation, Hisar, India: Haryana Agricultural University. SARMAH, M.K., NARWAL, S.S. and YADAVA, J.S. (1992). Smothering effect of Brassica species on weeds. In: Proc. First National Symposium Allelopathy in Agroecosystems (Eds., P. Tauro and S.S. Narwal) pp Hisar, India: Indian Society of Allelopathy, Haryana Agricultural University. THORNE, R.L.Z., WALLER, G.R., MCPHERSON, J.K., KENZER, E.G. and YOUNG, C.C. (1990). Autotoxic effects of old and new wheat straw in conventional tillage and no-tillage wheat soil. Botany Bulletin, Academia Sinica 31: WALLER, G.R. (1987). Allelochemicals: Role in Agriculture and Forestry. ACS Symposium Series No Washington DC: American Chemical Society. 606 pp. WALLER, G.R., KRENZER, E.G., MCPHERSON, J.K. and Mcgown, S.R. (1987). Allelopathic compounds in soil from no tillage v/s conventional tillage in wheat production. Plant and Soil 98: WANG, D. and OLOFSDOTTER, M. (1996). Growth characters of allelopathic and nonallelopathic rice. In: Abstracts I World Congress on Allelopathy. Abstract. pp. 72. Cadiz, Spain: International Allelopathy Society. WESTON, L.A. (1996). Utilization of allelopathy for weed management in agroecosysterns. Agronomy Journal 88: YADAV, J.S., NARWAL, S.S. and THAKRAL, S.K. (1994). Weed suppression potential in Brassica species. Abstract 1.7. Abstracts, International Symposium Allelopathy in Sustainable Agriculture, Forestry and Environment (Eds., S.S. Narwal, P. Tauro, G.S. Dhaliwal and Jai Prakash). pp. 88, Hisar, India: Indian Society of Allelopathy, Haryana Agricultural University. YOUNG, C.C., THORNE, R.L.Z. and WALLER, G.R., (1989). Phytotoxic potential of soils and wheat straw in rice rotation cropping systems of subtropical Taiwan. Plant and Soil 120:

61 Herbologia Vol. 12, No. 1, 2011 THE ECOLOGY AND SYNTAXONOMY OF WEED VEGETATION AT THE DINARIC ALPS (W. BALKAN) Sulejman Redţić Academy of Sciences and Arts of Bosnia and Herzegovina; Centre of Ecology and Natural Resources of the Faculty of Science, the University of Sarajevo Sarajevo, Bosnia and Herzegovina or Abstract A high level of weed vegetation diversity of Dinaric Alpes was determined using modified method of the Zürich-Montpellier school. From syntaxonomical standpoint, weed vegetation in this area is organized in one class, two sub-classes, four orders, 13 alliances (including one sub-alliance) and 44 communities at the level of associations. Main reasons for high both vegetation and syntaxonomic diversity are geographical and ecological position of the Dinaric Alps including of entire Bosnia and Herzegovina, their direction, as well as diversity of bedrock type, soil types, water regime of the stands, and a very high level of floristic diversity of climate. In light of current studies, total weed vegetation belongs to a unique class Stellarietea mediae R. Tx. et al. ex von Rochow Depending the use of agricultural land it can be distinguished two types of weed communities: the weed vegetation in wide-row crop and weed vegetation in cereals (small grains). Weed crop communities belongs to a sub-class Violenea arvensis Hüppe et Hofmeister ex Jarolímek et al. 1997, and the communites in cereals under the class Secalienea cerealis Rivas-Martínez, Báscones, T.E. Díaz, Fernández-González & Loidi The differentiation of these two sub-class significantly depends on the intensity of land use and the type of natural primary vegetation. Key words: weed vegetation, phytocoenology, classification, Stellarietea mediae, Violenea arvensis, Secalienea cerealis, habitat categorization, Bosnia and Herzegovina Nomenclature: Tutin et al. ( ); Hayek ( ) Introduction Understanding of weed vegetation and approach to classification Weed vegetation is a community that can develop in different crops. According to the traditional way of processing, weed vegetation is divided

62 S. Redţić into two types of communities: the weed vegetation in crop cultures (broadrow or wide-row crops) and weed vegetation in cereals (small grains). Weed of broad-row communities belongs to a sub-class Violenea arvensis Hüppe et Hofmeister ex Jarolímek et al. 1997, and the communities in small grains under the class Secalienea cerealis Rivas-Martínez, Báscones, T.E. Díaz, Fernández-González & Loidi In this paper, the traditional classification of the habitat of the weed vegetation (Rodwel et al. 2002) was applied. However, it is necessary to perform its classification in accordance with existing standards of land cultivation and the use of agricultural crops. Weed vegetation as a part of biodiversity Weed vegetation is an important bioindicator of the process of antropogenesis, both in time and space (Horvatić, 1934; Tüxen, 1950; Passarge, 1957a, 1957b; Redţić, et al. 2008; Šilc et al., 2008; Trinajstić, 2008). Weed flora and vegetation has developed and evolved along with the process of domestication of wild plants in the production of food. As the number domesticated plants grew and the number of weed species grew too. Thus, their number reached tens in each regional flora, and hundreds, even thousands in continental and global flora. Already evident that the weed species and their communities significantly reduce the yield of crops. In order to it the man from the earliest period of trying to find adequate measures for controlling weeds, and their sustainable management (Sadlo & Kolbek 1997; Jarolimek et al. 1997; Dupont 1999; Abdelkrim 2004; Chronopopulos et al To achieve a good practice are necessary key fundamental knowledge about of weed flora and vegetation of a given area. Investigations of the weed vegetation in Dinaric Alpes (it's hilly and mountainous area going from the Alps in the north-west to Šara and Pindos in the southeast and Rodops in the East, and Pannonia in the north) still have pronounced trend and the need, considering various aspects, such as classification, understanding of their structure and dynamics, and modern investigations of syntaxonomy (Oberdorfer 1983; Mucina 1993; Wilmanns 1993; Ellenberg 1996; Hovi 1996; Haveman et al. 1998; Borhidi 1996; Dessaint et al. 1997; Wezel 2000; Chytry et al. 2002; Kobayashi et al. 2003; Lososova 2003; Lososova et al. 2003; Aquilar et al. 2003; Romero et al. 2005). Particular attention has been paid to the modern synthetic investigations and syntaxonomical revision and objectification of certain types of weed vegetation, or vegetation complexes in both narrow and wider geographical regions (Kropaĉ et al. 1971; Holzner 1978; Krippelova & Mucina 1988; Korotkov et al. 1991; Stevanović et al. 1995; Solomakha 1996; Ĉarni et al. 2002; Lososova et al. 2004). 58

63 The ecology and syntaxonomy of weed vegetation at the Dinaric Alps.. Particular attention in previous investigations in phytogeography and classification of weed vegetation has been paid to the western Balkan (Batinica et al ; Marković 1979; Hulina 1979; Topić 1982; Horvat et al. 1974; Bleĉić & Lakušić 1976; Jovanović et al. 1986; Pavlović 1987; Pavlović-Muratspahić 1995). There were several attempts of phytogeographical differentiation and analysis of weed vegetation in previous phytocoenological investigations in the region of the western Balkan, and even whole Balkan Peninsula (Horvat 1960, 1962; Horvat et al. 1974; Kojić 1975; Dizdarević et al. 1979; Lakušić et al. 1979; Kojić & Pejĉinović 1982; Šumatić 1997; Kojić et al. 2005). The results obtained through the investigation of weed vegetation play major role in terms of its prevention and development of sustainable agricultural practice, as well as in ecological based combat against dominant weed species and getting better insight in ecology of alien species and their rational management, furthermore it is obligatory part of biodiversity evaluation of certain area ( Lososova et al. 2003, Redţić 2007a, 2007b). Weed vegetation play an important role in entire ecological and biological diversity of any area which is why it has been payed special care and attention to it (Mucina 1997; Ĉarni et al. 2002; Hulina 2002; Rodwell et al. 2002; Šilc 2005; Lososova et al. 2006; Redţić 2006). Many weed species are being threatened or extinct, representing true genes pool rarity both on the territory of Dinaric Alps and entire Bosnia and Herzegovina. The species Agrostema githago that used to be quite common in the past, true jewel of our crops, today is extremely rare. It has been recorded lately in the crop fields of Secale cereale L. on Glamocko polje and Rostovo. Similar situation relates to Anagallis foeniceae, Ajuga chamaepitys, Legousia speculum-veneris, Legousia hybrida, Kickxia spuria, Lamium amlexicaule and some others. Therefore, it is very important to investigate syntaxonomy weed vegetation as a reliable indicator of ecological diversity at the horizontal and vertical profile of Bosnia and Herzegovina and Dinarides as well (Redţić et al. 2000, 2002, 2008). Main objectives of this paper are: (i) to carry out syntaxonomical classification of weed vegetation types on both vertical and horizontal profile on the mountains of Bosnia and Herzegovina and entire of Dinaric Alpes on the basis of previous investigations in the light of modern methodology of Braun-Blanquet; (ii) too carry out syntaxonomic revision of complex and problematic weed vegetation types and certain syntaxa, and in the light of modern investigations and contemporary trends in the science of vegetation and (iii) to determine of main ecological features, pathway development as well as the needs for categorisation and classification of habitats and sustainable biodiversity management; 59

64 S. Redţić General characteristics of the investigated area General characteristics of investigated area mostly has men presentet in previous paper of same author (Redţić 2007). The study area is located between 42 and E. and 20 N and Geology. The Bosnian Dinaric Alps are heterogeneous, regarding geological and petrography characteristics. Mesozoic limestone sediments play a dominant role in the whole region. In some parts, Paleocene sediments cover large areas, while in the hilly and mountain belt towards northern part of the region dominant role play Jurassic and Triassic sediments. Paleozoic sediments occur sporadically, as well as basic and ultra basic eruptives (Ĉiĉić & Panić 1977). The largest part of the Balkans was not under the influence of the last glaciations, except for the peaks of the highest mountains. However, there are sporadic indirect glacial influences, e.g. at Mt. Vlašić, Maglić Mt., Bjelašnica Mt. and Vranica Mts. (Katzer 1926). Orography. The Bosnian Dinaric Alps mountains have direction northwest - southeast. The region is intersected by numerous river valleys with a direction north - south. Neretva rivers flowing from the north to the south. The vertical profile from the Adriatic sea towards the peaks in those mountains is to the highest peak on the Mt. Magilić 2387m. As a result there are clearly differentiated the following belts: Mediterranean, sub- Mediterranean, hilly belt, mountain belt, sub alpine and alpine belt (Redţiĉ et al. 2008). Hydrology: At the area of Bosnia is rich hydrological network. There are two basins: the Black Sea and the Adriatic. The main waterways in the Black Sea basin are the catchment areas of the river Una, Sana, Vrbas, Bosna, Drina and Tinja. Most of the water flowing to the Adriatic Sea in the Danube River Neretva and Cetina. Hydrological regime significantly affects to the character of the soil and the types of crops, and consequently on the structure and dynamics of weed communities (Redţić, 2010). Ecoclimate. As regards the climate, the region is very heterogeneous and dynamic. Mean annual temperatures are (Lakušić 1975; 1981; Redţić et al. 2008): Mediterranean region C Submediterranean C Hilly region 11-8 C Mountainous belt 7-4 C Sub alpine belt 3-0 C 60

65 The ecology and syntaxonomy of weed vegetation at the Dinaric Alps.. The wind is most frequently from the southwest and this wind has also a strong influence on the formation of vegetation cover. Ecoclimate is Mediterranean and sub-mediterranean, moderatecontinental, with the strong influence of the continental climate from the north-east, and mountain climate from mountain peaks (Milosaljević 1973). According to Graĉanin (1950) ex Redţić (1990) ecoclimate is warm and moderate humid and humide. There is arid period during summer season in Mediterranean region. Humidity is present throughout the year at the most other regions of Bosnia and Herzegovina. Soil conditions. In this area soils are very heterogeneous. Different types of calcareous and silicates terrestrial soils are dominant (Lakušić et al. 1982; Redţić 1990; Redţić et al. 2000, 2002). During the long past time natural soils have been much changed by human activity. Now, dominate anthropogenic soils, mostly different kind of hortisoils with variable of deepness and profile. Existing arable soils originating from luvisol, fluvisol, pseudogley (in lowland areas), and from cambisols and deeper humus accumulative soils in the mountainous area. The original soil type significantly affects the composition of weed communities and their development. Phytogeography. Considering phytogeography, investigated area belongs to three regions: (i) Mediterranean with Adriatic province, (ii) Eurosiberian- Boreamerican with Moesian and Illyrian province, as Province of relict pine forests as well and (iii) Alpine-High-Nordic region with High-dinaric province (Adamović 1907; Lakušić 1969; Redţić et al. 2008). Adriatic provinces are characterized by a evergreen forests of oak Quercion ilicis. Moesian province is distinguishes presence of climatogenous vegetation of thermophile forests from association Quercetum farnetto-cerris in hilly belt, forests of sessile and Turkey oak Quercetum petraeae-cerris in the upper part of hilly belt, and acidophilus forests of sessile oak Quercetum petraeae in montane belt (Stefanović et al. 1983; Jovanović et al. 1986). Illyrian province is distinguished by climatogenous forests of fir and spruce from alliance Piceion abietis, and beech forests Fagion illyricum s.lat (Lakušić et al. 1978). The Province of relict pine forests represented by alliances Pinion halepensis, Pionion heldreichii and Erico-Pinion (Redţić et al. 2008). Alpine-High-Nordic region, High Dinaric province is distinguished by the presence of turfs on limestone from alliances Festucion bosniacae, Seslerion juncifoliae, and Gentiano-Crepidion dinaricae (Redţić 1990, 1999, 2003). 61

66 S. Redţić Material and methods More than 550 relevees made in various habitats on both horizontal and vertical profile on the Bosnian Dinaric Alps during long term vegetation investigations using modern European methodology by Braun-Blanquet (1964) has been analysed. Determination of weed communities has been carried out on the basis of the results from analytic and synthetic phytocoenological tables, and in accordance with the Code of phytosociological nomenclature (Weber et al. 2000). Besides determination of floristic composition and assessement of quantitative distribution and forms of distributions for each registered species, for each relevé have been also determined the following habitat attributes: coordinates, altitude, aspect, slope, bedrock and soil type, general vegetation coverage. The previously published data relevant for this area (Slavnić 1951; Horvat 1960; Batinica et al ; Lakušić et al. 1978, 1979, 1982; Dizdarević et al. 1979; Redţić 1990, 1999, 2003, 2006, 2007a, 2007b) have been used in analysis of syntaxonomic weed diversity. Syntaxonomic overview includes determination of syntaxa at the level of class, order, alliance (suballiance), and association and subassociation in certain cases. The nomenclature for the most taxa at the class level is after Conspectus of classes of European vegetation (Mucina 1997), and after The Diversity of European Vegetation (Rodwell et al. 2002), and for some after Oberdorfer (1983). Identification and determination of type of habitat of weed community has been in according of EUNIS methodology (Rodwell et al. 2002). In a review of community, indicator for the habitat type is indicated by an asterisk (*). Syntaxonomic overview Results Intensive comparative investigations of ecological and floristic differentiation of vegetation of weed communities on Dinaric Alps it was found out 44 communities on the level of association, 13 alliances, 4 orders, two sub-classes and one class. On the basis of the results, and their revision in the context of modern investigations in vegetation science, the following syntaxonomic differentiation of the weed vegetation on continental Dinaric Alps is proposed: (Classes have been presented with uppercases and bold, orders with uppercases and bold italic, alliances with lowercases and associations with ordinary cases). 62

67 The ecology and syntaxonomy of weed vegetation at the Dinaric Alps.. Weed vegetation of field crops, gardens and wasteland Class: Stellarietea mediae R. Tx. et al. ex von Rochow 1951 [N 67] (*) [Syn.: Stellarietea mediae (Br.-Bl. 1932) R. Tx. Lohm. Prsg. 1950; Chenopodietea Br.-Bl p.p.; Secalino-Stellarienea Rivas Goday 1964;; Stellarienea mediae Hüppe & Hofmeister ex Théurillat, Aeschimann, Küpfer & Spichiger 1995]. I. Weed vegetation of mostly cereals (small grains) Sub-Class: Secalienea cerealis Rivas-Martínez, Báscones, T.E. Díaz, Fernández-González & Loidi 1991 [N67 A ] (*) [Incl.: Class: SECALIETEA Br..Bl. in Br.-Bl. et al. 1952] Weed vegetation of mostly cereals crops on moderately humid and moderately nitrified soil at warmer habitats. Order: Atriplici-Chenopodietalia albi [N67A A ] (*) [Incl.: Aperetalia spica-venti J.Tüxen & Tüxen in Malato-Beliz, J. Tüxen & Tüxen 1960; Spergularietalia arvensis Hüppe & Hofmeister 1990; Chenopodietalia medioeuropaea Tx. 1937; Chenopodietalia albi Tx. et Lohmeyer in Tx. 1950; Sperguletalia arvensis Hüppe et Hofmeister 1990; Secali-Violetalia arvensis Br.-Bl. et Tx. ex Sissingh in Westhoff et al p.p. min.; Anagallidetalia R. Knapp 1948 p.p.; Aperetalia spicae-venti J. Tüxen et Tx. in Malato-Beliz et al p.p.; Lolio-Linetalia J. Tüxen et Tx. in J. Tüxen 1966 p.p. min.; Polygono-Chenopodietalia auct. p.p.; I n c l.: Solano-Polygonetalia Sissingh in Westhoff et al (pro subordine)]. Weed communities of mostly cereals crops at the warmer habitats in SE Europe Acidophilous segetal communities of cereal and root crops in temperate to submeridionale zones of the Euro-Siberian region. Those are weed communities of mostly cereals at the warmer habitats in SE Europe. Alliance: Panico-Setarion Sissingh in Westhoff, Dijk et Passchier 1946 [N67A04] (*) [S y n.: Spergulo-Erodion J. Tüxen 1966; Spergulo-Erodion J. Tüxen ex Passarge 1964; Digitario-Setarion Sissingh in Westhoff et al em. Hüppe et Hofmeister 1990 ; I n c l.:panico-setarienion (Siss. inwesth. et al. 1946) Oberdorfer 1957; Digitario-Setarienion (Siss. inwesth. et al. 1946) Th. Müller in Oberdorfer 1983]. 63

68 S. Redţić Segetal communities of root crops, vegetables and special crops in the temperate to submeridionale European zone. Those mostly weed communities of summer cereals dominated by graminoids and root crops. Ass.: Setarietum viridis Lakušić et al Ass.: Erigerono-Setarietum glaucae Šumatić 1991 Ass.: Papaveretum rhoeadis Redţić 2007 Alliance: Scleranthion annui (Kruseman et Vlieger 1939) Sissingh inwesthoff, Dijk et Passchier 1946 [N67A06] (*) [S y n.: Aperion spicae-venti Tüxen in Oberdorfer 1949; Agrostion spicae-venti Tüxen ex von Rochow 1951; Arnoseridion minimae Malato-Beliz, J. Tüxen & Tüxen 1960; Aphanion arvensis Malato-Beliz, J. Tüxen & Tüxen 1960; Rumicion bucephalophori Nezadal 1989]. Segetal communities of cereals and legume grain mixtures, less so of rape, young meadow clovers and clover grass mixtures and but also root crops; they occur in the European temperate zone and occasionally in the boreale and submeridionale zones of the Euro-Siberian region. Those are European arable weed communities of neutral to acid loamy and sandy loam soils. Ass.: Aphano arvensi-matricarietum recucitae (R.Tx. 1937) Redţić 2007 (Syn.: Alchemillo arvensis-matricarietum chamomillae R. Tx. 1937) Ass.: Lathyro-Aperetum R. Tx Ass.: Scleranthetum annui Redţić 2007 Ass.: Vulpietum myuris Lakušić et al Order: Centauretalia cyani R. Tx., Lohmeyer et Preising in Tx. ex von Rochow 1951 [N67B] (*) [S y n.: Secalinetalia Br.-Bl. 1931; Secalietalia Br.-Bl.in Br.-Bl., Gajewski, Wraber & Walas 1936; Papaveretalia rhoeadis Hüppe & Hofmeister in Théurillat, Aeschimann, Küpfer & Spichiger 1995; Centaureetalia cyani Tüxen, Lohmeyer & Preising in Tüxen 1950; Papaveretalia rhoeadis Hüppe et Hofmeister 1990]. Spring and summer segetal communities of cereal crops on base rich and silicates soils in central and SE Europe. Alliance: Caucalidion lapulae R. Tx. ex von Rocher 1951 [N67B02] (*) [S y n.: Secalion medioeuropaeum Tx. 1937; Caucalidion lappulae (eurosibiricum) Tx. 1950; Caucalidion platycarpi auct; Caucalis-Conringia- Orlaya Vereine Meusel 1940; Triticion sativae Klika 1941; Consolido- 64

69 The ecology and syntaxonomy of weed vegetation at the Dinaric Alps.. Eragrostion poaeoidis Soó et Timár in Timár 1957 p.p.; I n c l.: Triticion sativae Kruseman et Vlieger 1939 pro suball.); Delphinietum consolidae R. Knapp 1948 (pro associatione sensu latissimo)]. Spring segetal communities of cereal crops on base rich soils in central and SE Europe Ass.: Stachydetum annuae Redţić 2007 Ass.: Anthemi-Consolidetum orientalis Slavnić 1944 corr. Redţić hoc loco [Syn.: Ass.: Anthemis-Consolida orientalis Slavnić 1944] Ass.: Veronicetum hederifolio-triphyllii Slavnić 1944 corr. Holzner 1973 [Syn.: Ass.: Veronica hederifolia-veronica triphyllos Slavnić 1944] Ass.: Stachydi-Ajugetum chamaepytis Slavnić 1944 corr. Redţić hoc loco [Syn.: Ass.: Stachys-Ajuga chamaepytis Slavnić 1944] Ass.: Cirsietum arvensis Redţić 2007 Alliance: Centaurion cyani Redţić 2007 [N67B02 B ] (*) [S y n.: Caucalidion lapulae R. Tx. ex von Rocher 1951 p.p.] Charact. Species: Agrostemma githago, Centaurea cyanus, Consolida regalis, Legousia hybrida, Ranunculus arvensis, Sherardia arvensis, Vicia hirsute and Vicia tetrasperma. Summer weed communities of cereal crops on base rich and acide soils in higher position of SE Europe. Ass.: Agrostemo-Centauretum cyani Redţić 1980 em Ass.: Centauretum cyani Redţić Redţić 2007 Alliance: Scherardion arvensis Kropác et Hejný in Kropác 1978 [N 67B09] (*) Segetal communities in cereal and root crops in mildly warm areas of the temperate European zone. Arable weed communities at the central and SE Europe.. Ass.: Kickxietum spuriae Krus. et Vlieg Alliance: Galeopsidion speciosae-pubescentis Kojić 1972 [N 67B09 B ] (*) Summer and autumn segetal communities in warmer habitats at the plane 65

70 S. Redţić terrain in Moesian Province, mostly. Ass.: Galeopsi-Calystegietum sepii Stepić 1984 Ass.: Erigerono-Setarietum glaucae Šumatić 1991 Ass.: Cirsio-Stachyetum palustris Šugar 1972 II. Weed vegetation on moderately humid and moderately nitrified soils with root crops Sub-Class: Violenea arvensis Hüppe et Hofmeister ex Jarolímek et al.1997 [S y n.: Violenea arvensis Hüppe et Hofmeister 1990; Secalienea Rivas- Martínez 1987; Stellarienea mediae Rivas-Martínez et al. 2001] Order: Polygono-Chenopodietalia Tüxen & Lohmeyer in Tüxen 1950 em. J. Tüxen in Lohmeyer et al [N 67A AA ] (*) [S y n.: Solano nigri-polygonetalia convolvuli (Sissingh in Westhoff, Dijk & Passchier 1946) O. Bolòs 1962; Chenopodietalia albi (Sissingh in Westhoff, Dijk & Passchier 1946) Tüxen & Lohmeyer in Tüxen 1950; Polygono- Chenopodietalia albi Tüxen & Lohmeyer in Tüxen 1950 em. J. Tüxen in Lohmeyer & al. 1962; Solano nigri-polygonenalia convolvuli Sissingh in Westhoff, Dijk & Passchier 1946 (corresp. name), Polygono-Chenopodietalia J. Tüxen in Passarge 1964; Eragrostietalia J. Tüxen ex Poli 1966]. Alliance: Calendulo arvensi-heliotropion europaei Trinajstić 2007 Crops weeds over the Adriatic coastal area in Herzegovina. Ass.: Hibisco-Sorghetum halapensis Horvatić et Hodak 1960 Ass.: Tribulo-Amaranthetum Hodak 1962 ex Pandţa et al Alliance: Polygono-Chenopodion polyspermi Koch 1962 em. Sissingh [N 67A05] (*) [S y n.: Eu-Polygono-Chenopodienion polyspermi Oberdorfer 1957; Spergulo-Oxalidion Görs in Oberdorfer et al. 1967; Oxalidion europaeae (Görs 1967) Passarge; Veronico-Euphorbion pepli Sissingh 1942 p.p.; Eu- Polygono-Chenopodion polyspermi Koch 1926 em. Sissingh in Westhoff et al p.p.; Veronico-Euphorbion Sissingh ex Passarge 1964 p.p.; Spergulo-Erodion J. Tüxen ex Passarge 1964 p.p.; Incl.: Eu-Polygono-Chenopodienion (Sissingh in Westhoff et al. 1946) Oberdorfer 1957 em. Th. Müller et, Oberdorfer in Oberdorfer 1983 p.p. max., Galinsogo- Euphorbenion pepli Passarge 1981 p.p.] 66

71 The ecology and syntaxonomy of weed vegetation at the Dinaric Alps.. Segetal communities in root crops, some legume-grain mixtures and young clover-grass mixtures, mainly in the temperate zone but also in the boreale and submeridionale zones of the Euro-Siberian region. Weed communities of root crops including summer cereals dominated by herbs. Ass.: Stellarietum mediae Prodan 1939, Hadaĉ 1969 [Syn.: Ass.: Stellarietum mediae Pavlović-Muratspahić 1995, Incl. Galeopsido tetrachiti-stellarietum mediae Passarge 1975] Ass.: Setario-Heliotropietum europaei Slavnić 1944 corr. Redţić hoc loco [Syn.: Setaria-Heliotropium europaeum Slavnić 1944] Ass.: Panico-Portulacetum oleracei Slavnić 1944 corr. Redţić hoc loco Ass.: Panicum-Portulaca oleracea Slavnić 1944 Ass.: Galeopsido-Chenopodietum polyspermi Oberdorfer Ass.: Setario-Stachyetum arvensis Oberdorefer 1957 Ass.: Panico-Galinsogetum parviflorae R.Tx. ex Becker 1942 Ass.: Setario pumilae-galinsogetum parviflorae R.Tx Ass.: Cirsio-Stachydetum palustris Šugar 1973 Ass Veronico persicae-lamietum purpuraeae Redţić 1978 em. Redţić hoc loco Sub-Alliance: Digitario ischaemi-setarienion viridis (Sissingh in Westhoff, Dijk & Passchier 1946) Oberdorfer 1957 Ass.: Setario-Galinsogietum parviflorae R. Tx. em. Muller et Oberdorfer Ass.: Digitario-Galinsogetum parviflorae Tüxen & Becker 1942 Ass.: Digitario-Setarietum viridis Redţić 1978 em. Redţić hoc loco Alliance: Fumario-Euphorbion Mull. ex Gors 1966 [S y n.: Veronico-Euphorbion pepli Sissingh 1942 p.p; (Eu-)Polygono- Chenopodion polyspermi Koch 1926 em. Sissingh in Westhoff et al p.p.; Veronico-Euphorbion Sissingh ex Passarge 1964 p.p.; Fumario- Euphorbion sensu Passarge 1981 non Görs 1966, Veronico-Euphorbion sensu Mucina in Mucina et al non Sissingh ex Passarge 1964; Galinsogo-Euphorbenion pepli Passarge 1981 p.p. min.] Segetal communities in root crops, vineyards and perennial fodder crops growing in warm areas of the temperate to submeridionale zones of the Euro-Siberian region Ass.: Mercurialietum annuae Kruseman et Vlieger ex Sissingh in Westhoff et al. em. Th. Müller in Oberdorfer

72 S. Redţić Ass.: Setario-Veronicetum pollitae Oberdorfer 1957 Ass.: Fumarietum officinalis Redţić 2007 Ass.: Stellario-Veronicetum tournefortti Redţić 2007 Alliance: Spergulo-Oxalidion [N 67B09] (*) European weed communities of moist loamy acids soils on higher position with potato. Ass.: Rumici acetosellae-scleranthetum annui Trinajstić 1980 Ass.: Panico-Chenopodietum polyspermi R.Tx Alliance: Veronico politae-taraxacion Kropác et Hadac in Kropác et al [N 67B12] (*) Weed communities in permanent fodder crops on loamy and clayey soils Ass.: Ranunculo sardoi-taraxacietum Pavlović-Muratspahić 1995 Order: Eragrostetalia J.Tx. ex Poli 1966 [N 67D] (*) [S y n.: Eragrostietalia J. Tüxen 1961; J. Tüxen in Lohmeyer et al J. Tüxen in Matuszkiewicz 1962; Solano-Polygonetalia (Siss. in Westhoff et al. 1946) O. de Bolós 1962 p.p.; Solano-Polygonetalia O. de Bolós 1962 em. Brullo et Marceno 1980 p.p.; Eragrostietalia J. Tüxen 1961 em. Soó 1971]. A set of weed communities that develop in hot, dry part of Europe. In Bosnia and Herzegovina those communites egsist in sub Panonian and Panionian region (Posavina and Low Herzegovina). Alliance: Eragrostion R.Tx. ex Oberdorfer 1954 [S y n.: Amaranthion Tx. et Preising 1942; Eragrostion Tx. in Slavnić 1944; Tribulo-Eragrostion poaeoidis Soó et Timár in Timár 1957 p.p. max.,; Consolido-Eragrostion poaeoidis Soó et Timár in Timár 1957 p.p. min.; I n c l.: Eragrostienion Tx. 1950]. Segetal communities of root crops, mainly vegetables, vineyards, orchards and special crops (tobacco, asparagus), and also ruderal habitats in the Pannonian subregion with localities in the Balkan Peninsula and Pontic province. Ass.: Hibisco-Eragrostetum (Felföldy 1942) R.Tx

73 The ecology and syntaxonomy of weed vegetation at the Dinaric Alps.. Ass.: Panico-Eragrostidetum R. Tx Ass.: Eragrosti majoris-eragrostetum minoris Slavnić 1944 corr. Redţić hoc loco [Syn.: Ass.: Eragrostis maior-eragrostis minor Slavnić 1944] Ass.: Aristolochio-Convolvuletum arvensis Ubrizsy 1967 Discussion From a syntaxonomic standpoint, plant coverage of this area could be divided into one class, two sub-classes, 13 alliances and 44 communities of the level of association (Tab. 1). Table 1. Numerical structure of syntaxa of weed communities Class Sub-class Numberof orders Number of alliances Number of associations Secalienea cerealis Stellerietea mediae Violenea arvensis (Syn.: Stellarienea) The syntaxonomy is very complex and uneven which is confirmed by many relevant authors in the field of vegetation science, both classic and modern ones (Braun-Blanquet 1946; Oberdorfer 1983; Rodwell et al. 2002). Due to changing pattern of habitat's conditions which is very extreme, this vegetation type is subject to swift dynamics followed by transformations because of which there are different approaches and opinions regarding its classification. Comparative ecological and sytaxonomic research of weed vegetation on horizontal and vertical profile of B&H Dinaric Alps that has been conducted over the last 30 years (Batinica et al ; Redţić 1977; Lakušić et al. 1978; Pavlović 1987; Pavlović-Muratspahić 1995; Redţić 1990; Šumatić 1987; Redţić et al. 2000, 2002, 2008), has shown need for revision of its contemporary syntaxonomy and for development of new syntaxonomy patterns. New approach should be based upon ecological character of habitat ( hydrothermic regime, intensity and forms of anthropogenous impact ), as well as floristic composition of the community. Within so called tertiary vegetation, weed vegetation is the most liable to changes (weed and vegetation of abandoned places). Thus, these investigations point out the importance of forms and intensity of 69

74 S. Redţić anthropogenous impacts onto weed vegetation's habitat which is directly related to floristic assembly of certain communities and their syntaxonomic status. Modern literature on diversity of European vegetation (Roodwell et al. 2002; Benventuti 2004; Lososova 2004; Pandţa et al. 2005; Lososova et al. 2006; Kropaĉ 2006; Sanda et al. 2008; Šilc 2008; Šilc & Ĉarni 2007; Šilc & Vrbniĉanin 2008; Šilc et al. 2009) placed entire weed vegetation into single class Stellarietea mediae. Same approach had Mucina (1997) making conspectus of European vegetation's classes. In the sense of these investigations, weed vegetation on Dinaric Alps is being clearly differentiated into two sub-classes: Secalienea cerealis and Violenea arvensis. Despite the anthropogenic pressures, are still present in some parts of the Dinarides, especially at higher altitudes, communities of sub-class Secalienea cerealis. In the most parts of Europe these communities have disappeared due to intensive agriculture production and use of herbicides Conclusions Based on the results on the structure and dynamics of weed vegetation in the area of Bosnian-Herzegovinian Dinarides, it can be concluded the following: 1) Weed vegetation is still poorly investigated. This is particularly true for hilly and mountainous areas at the higher altitudes; 2) The weed vegetation are clearly differentiated in the horizontal and vertical profile of the Dinarides. Weed communities in the Mediterranean and sub-mediterranean zone are significantly different in relation to the mountains and the mountain belt; 3) In terms of syntaxonomy, weed vegetation is united into a unique class Stellarietea mediae, with a two sub-classes: Secalienea cerealis and Violenea arvensis; 4) In terms of ecology, weed vegetation is divided into four types: (i) the thermophilous at the humide habitats, (ii) the thermophilous at the dry habitats, (iii) frigorifileous at the humide habitats and (iv) frigorifileous at the dry habitats; 5) It is necessary to implement modern intensive studies of the structure and dynamics of weed vegetation on the Dinarides in order to know their syntaxonomy, and 70

75 The ecology and syntaxonomy of weed vegetation at the Dinaric Alps.. 6) To identified weed communities in Bosnia and Herzegovina indicate a large number of habitats important for Habitat Directive. Acknowledgement. This work is a part of the investigations carried out within the project Obrasci ekološko-sintaksonomskog diverziteta u procjeni stanja i nosivog kapaciteta ekosistema životne sredine The Petterns of ecologic and syntaxonomic diversity in the assessment of state and carryng capacity of ecosystems of environment ( a/07; ; Kanton Sarajevo. Ministarstvo obrazovanja i nauke, Prirodno-matematiĉki fakultet Univerziteta u Sarajevu (Project Manager: Sulejman Redţić). References ABDELKRIM, H. 2004: A contribution to the ecology and phytosociology of weed vegetation and fallow land communities in the Algerian phytogeographical sector (Algeria), Phytocoenologia, 34 (2), ADAMOVIĆ, L. 1907: Pflanzengeographische tellung und Gliederung der Balkanhalbinsel. Aus der Kaiserlich-Koniglichen hof und Staatsdruckerel, Wien, 91 pgs. + 3 flancengeographishen Karten. AQUILAR, V., C. STAVER & P. MILBERG, 2003: Weed vegetation response to chemical and manual selective ground cover management in a shaded coffee plantation, Weed Research, 43 (1), BATINICA, D., V. STEFANOVIĆ, Ţ. BJELĈIĆ, Ţ. & LJ. MIŠIĆ, : Vegetacijska karta Jugoslavije - teritorij SR BiH, podruĉje Romanije, Jahorine, Trebevića, doline Praĉe i Miljacke. The Study of Biol. inst. Univ., Sarajevo. BENVENUTI, S., 2004: Weed dynamics in the Mediterranean urban ecosystem: ecology, biodiversity and management, Weed Research, 44, BLEĈIĆ, V. & R. LAKUŠIĆ, 1976: Prodromus biljnih zajednica Crne Gore. Glas.Republ. zavoda zast.prirode Prirodnjackog muzeja, Titograd, 9, BORHIDI, A An annotated checklist of the Hungarian plant communities, I. The nonforest vegetation. In Borhidi, a. (ed.) - Critcal revision of the Hungarian plant communities. Janus Pannonius niversity, Pécs, BRAUN-BLANQUET, J. 1964: Pflanzensoziologie. Springer Verlag, Wien - New York. CHRONOPOULOS, G., M. THEOCHAROPOULOS & D. CHRISTODOULAKIS, 2005: Phytosociological study of Hirschfeldia incana (L.) Lagraze-Fossat (Cruciferae) communities in mainland Greece, Acta Botanica Croatica, 64 (1), CHYTRY, M., L. TICHY, J. HOLT & Z. BOTTA-DUKAT, 2002: Determination of diagnostic species with statistical fidelity measures, Journal of Vegetation Science, 13, ĈARNI, A., M. KOSTADINOVSKI & V.MATEVSKI, 2002: Vegetacija na pohojenih rastišćih v Republiki Makedoniji, Hacquetia, 1 (2), ĈIĈIĆ, S. & J. PANIĆ (eds.) 1977: Geologija Bosne i Hercegovine. Knjiga III: Kenozojske periode.geoinţenjering. Sarajevo. DESSAINT, F., R. CHADOEUF &. G. BARALIS, 1997: Nine years soil seed bank and weed vegetation relationship in an arable filed without weed control, Journal of Applied Ecology, 34 (1),

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81 Herbologia Vol. 12, No. 1, 2011 ECOLOGICAL CHARACTERISTICS OF ASS. PANICO- GALINSOGETUM TX. ET BECK IN POTATO CROP Olivera Ilić and Ljiljana Nikolić Faculty of Agriculture, Novi Sad, Dositej Obradovic Sq. 8, University of Novi Sad, Serbia Abstract This paper presents the results of environmental and phytocenological analysis of weed plants in the conventional potato production in the experimental plots in Beĉej. The study was done the on untreated plots where only cropping practices were soil tillage and planting, with no weed control. Stands of association Panico-Galinsogetum Tx. Beck et. 1942, were diagnosed on the experimental plots with typical segetal (on arable land) weed community in broadleaf crops. Floristic composition of this association includes 29 species, with the highest degree of presence of Amaranthus retroflexus, Panicum crus-galli, Cirsium arvense, Sorghum halepense, Convolvulus arvensis and Bilderdykia convolvulus. Value analysis of environmental index, calculated on the basis of a covering values, indicating moderately wet (F 3 = 53.5% or 18 species), neutral to slightly acid soil (R 3 = 78.5% or 22 species), rich with biogenic material (N 4 = 56.7% or 21 species), with a mediate humus content (H 3 = 95.2% or 23 species). The observed weed stands are generally present on well aerated (D 4 = 54.5% or 19 species, D 3 = 45.1% or 8 species), nonsaline habitats (S_= 86.2% or 22 species), with a favorable light (L 4 = 55.7% or 24 species) and thermal (T 4 = 78.6% or 18 species) regime, which is consistent with a moderate continental climate conditions (K 3 = 98.3% or 25 species). Keywords: Ass. Panico-Galinsogetum Tx. Beck et. 1942, ecological indices, potato crop. Introduction The understanding of biological and ecological characteristics of weed plants is of fundamental importance for the successful weed control (Ĉanak et al., 1981; Nikolić et al., 2008; Ilić et al., 2009). By knowing the basic characteristics of weed species (floristic composition, abundance, time of occurrence, time of flowering and fruit bearing, method of reproduction, the attitude towards cultivated plants and to changes in environmental conditions, etc.), it is possible that with human

82 Ilić and Nikolić intervention such conditions are created that will interfere with the normal develop of weeds or lead to their gradual withdrawal. Damages to crop production, in this case potato production, caused by weeds are severe, diverse and permanent (Šinţar et al., 1988; Blake, 2000; Týr, 2008). Modern methods of weed control include a large number of various measures. Integral measures of protection against weeds are a complex system of various measures, which are dependent on the floristic composition, sinecological and other characteristics of agricultural phytocoenoses (Kovaĉević and Momirović, 2008). Improvement of the potato production in Serbia is possible with the rational application of appropriate cultural practices and integrated measures of protection and weed control. The aim of this study was to analyze phytocenological and environmental characteristics of weeds in potato crops in order to find the appropriate measures in their prevention and control. Materials and methods Phytocenological and environmental analysis of the weed vegetation in potato crop (Solanum tuberosum L.) was conducted in a three-year period ( ) on experimental plots in the vicinity of Beĉej. This paper contains a review of weed species in the control treatment of the experiment that included only tillage and planting without any measures of crop protection. Control treatments were 25 m 2 plots with 5 replications. Phytocoenological recording of vegetation covered the whole growing season of potatoes in all three years of research. Floristic-phytocoenological studies were carried out following the method of the Swiss-French school of Braun- Blanquet (Braun-Blanquet, 1964). The plant material was determined by Josifović ed. ( ), Javorka and Csapody (1975) and Tutin ( ). Nomenclature is given by Josifović ed. ( ). Sintaxonomic position of the community is given by Kojić et al. (1998). Ecological indices are given by Landolt (1977), and ecological analysis was made on the basis of the cover values for each species. Results and discussion Floristic-phytocenological analysis of weeds in conventional potato production showed the development stands of the association Panico- Galinsogetum (=as. Panicum crus-galli-galinsoga parviflora) in the 78

83 Ecological characteristics of ass. Panico-galinsogetum Tx. Et Beck in... experimental area. It is most typical segetal weed community in our country (Kojić et al., 1985, 1988, 1992, 1998). Present association has the following sintaxonomic position: Class Stellarietea mediae Tx., Lohm. et Prsg Order Chenopodietalia albi Tx., Lohm. et Prsg Alliance Poligono-Chenopodion Koch 1926 em Siss Association Panico-Galinsogetum Tx. Beck et Floristic composition, qualitative and quantitative participation of weed species in association Panico-Galinsogetum, is shown in synthetic fitocenological table (Table 1). The stands of the association Panico-Galinsogetum in potato crop were build up by 29 weed species. The relative floristic poverty is the consequence of a number of cultural practices and frequent application of herbicides. Numerous results suggest that constant application of herbicides caused significant depletion of the weed flora and lead to changes in its composition and structure of weed communities (Mišović et al. 1988; 1992). Hence, many characteristic species of the association, order and class are under-represented or completely absent. According to the results of Stefanović (1984), in association Panico- Galinsogetum of broadleaf crops in northeastern Serbia, 85 weed species are present. A smaller number of species (58) was found in Timoĉka Krajina (Kojić et al., 1992), or Maĉva, 43 weed species (Kojić et al., 1988). The floristic composition and structure of potato crop weed communities in plains (Šinţar, 1982) and mountain areas (Kojić et al., 1985; Šinţar et al., 1988), significant qualitative and quantitative differences were found. The same authors reported that the plain area is floristically more rich with 59 species (total cover value of 6530), compared to the hilly area with 56 species (total cover value of 3470). This study showed that the characteristic species of association, Panicum crus-galli, is represented with in a high number and had a high degree of presence (1235). The high prevalence can be correlated with the values of ecological indices for Panicum crus galli (Table 1) which are showing that this species is well adapted to prevailing environmental conditions that are found in the experimental area (Fig. 1). Second characteristic species, Galinsoga parviflora, it is somewhat less frequent because of the greater sensitivity to herbicides. For the same reason, relatively few species builds up a distinctive community: Amaranthus retroflexus, Panicum crus-galli, Cirsium arvense, Sorghum halepense, 79

84 Ilić and Nikolić Convolvulus arvensis and Bilderdykia convolvulus. Our results are in agreement with the results of Kojic et al. (1988), while Ajder (1992) showed slightly higher degree of cover values and the degree of presence of characteristic species of the association. Analysis of covering value of certain weed species, showes the closer features of its characteristics. Three groups of weed species are distinguished: a) species with high covering values ( ), b) species with medium covering values ( ) and c) species with low covering value (5-100). The first group includes species with the largest covering values, which are of importance for establishing certain cenological relations in the community, and these are: Amaranthus retroflexus, Panicum crus-galli and Cirsium arvense. The second group with medium covering values includes: Sorghum halepense, Convolvulus arvensis, Polygonum persicaria, Solanum nigrum, Polygonum lapatifolium, Setaria glauca and Matricaria chamomilla. The greatest number of weed species, 18, have low covering values, and those are: Galinsoga parviflora, Agropyrum repens and Matricaria inodora. Vertical stratification of the above ground plant cover in the stands of this association is well expressed, so it clearly demonstrates three layers. The bottom layer consists of weeds which usually reach the height of 5 to 30 cm, such as: Stellaria media, Convolvulus arvensis, Bilderdykia convolvulus, Capsella bursa-pastoris, Portulaca oleracea and others. The middle layer is the richest in species. Species that build it usually reache the height of 30 to 80 cm and they are: Cirsium arvense, Galinsoga parviflora, Polygonum lapathifolium, Chenopodium album, Agropyrum repens and others. Upper layer, which can reach height over 100 cm, consists of: Panicum crus-galli, Amaranthus retroflexus, Sonchus arvensis and Sorghum halepense. Structure of weed community is in close interdependence with environmental factors. With the change of environmental factors floristic composition and structure of weed communities are changed. The relationship and interdependence of weeds and environmental factors is expressed through the environmental index. The values of ecological indices for weeds in Panico-Galinsogetum association are calculated with the use of cover values and are shown in Figure 1. 80

85 Ecological characteristics of ass. Panico-galinsogetum Tx. Et Beck in F1 F2 F3 R2 R3 R4 N3 N4 N5 H2 H3 H4 D2 D3 D4 S- S+ L3 L4 L5 T3 T4 T5 K2 K3 K4 Figure 1. The percentages of the ecological indices for the weed flora in a potato crop Analysis of ecological indices for the humidity showed a high participation of mesophytes (F 3 ) adapted to temperate wetlands (53.5%, 18 species). Also significant is the participation of sub - xerophytes (F 2 ), indicators of moderate dry sites (38.1%, 10 species). Only one species (8.4%) adjusted to the very dry habitat (F 1 ) was observed. Also, the average value of the index (2.6) indicates moderate humidity of the substrate. Analysis of ecological indices for ph value of the environment showed a predominance (78.5%, 22 species) of neutrophilic plants (R 3 ). Plants that grow in the neutral to slightly alkaline habitats (R 4 ) are represented by 11.8% (5 species), while the indicators of the acidic habitat (R 2 ) present with 9.7% (2 species). The mean value of the index (3.1) also indicates a neutral to slightly acidic medium. Based on the analysis of ecological indices for the content of biogenic minerals especially the nitrogen compounds, the dominance of eutrophic indicators of habitat (N 4 ) with 56.7% (21 species) was observed. Much smaller share of plants (21.6%, 6 species) that grow on the site with moderate content of biogenic minerals (N 3 ) was observed. Also, there were two species (21.7%) which are characteristic indicators of eutrophic ecosystems (N 5 ). The average value of the ecological indices (3.9) also indicates the eutrophic conditions of the habitat. 81

86 Ilić and Nikolić The analysis of the value of ecological indices for the content organicmineral compounds of humus showed a predominance (95.2%, 23 species) of indicators of habitats with medium concentrations of these substances (H 3 ). The indicators of habitats with low content of organic matter were present with a significantly lower percentage (H 2-3.5%, 3 species) and indicators of habitat relatively rich in humus content H 4 (1.3%, 3 species). An average value of the index for the humus content (3.0) indicates the conditions with medium humus content. Based on the analysis of the ecological index for aeration (dispersion) a significant presence of indicators of well-aerated medium (D %, 19 species) was observed. Only indicators of well aerated soils (D 3 ) were present with 45.1% (8 species). Contrary to that, only two species (0.4%) that are adapted to extremely well aerated medium (D 2 ) were recorded. Good aeration of medium is shown by the average value of this ecological index (3.6). Bio-indicator values for salinity indicate the dominance of non-saline environment (S - ) with 86.2% or 22 species. Partially saline areas (S + ) are indicated by the presence of 7 species (13.8%), which can tolerate elevated levels of Na + ions. Analysis of environmental indices for the light showed a dominance of light indicators (L 4 ) with 24 species (55.7%). Indicators of semi-shade (L 3 ) are present with a 4 species (39.9%). Only one species (4.4%) is an indicator of very sunny sites (L 5 ). The results indicate a favorable light regime of the experimental area, which is also shown by the mean value of the index (3.9). The analysis of the environmental index values for temperature has shown the dominance it was the dominance of thermophilic plants (T 4 ), indicators of the warm habitats with 78.6% (18 species). Indicators of a moderate warm habitats (T 3 ) and the indicators of the warmest habitats (T 5 ) are presented with lower percentages, 12.4% (6 species) and 9.0% (5 species), respectively. A favorable temperature regime of the experimental area is indicated by the mean value of ecological indices for the temperature (4.0). As for the environmental index of continentality, the results indicate a dominant share of plants that live in conditions of moderate climate (K %, 25 species). Plants characteristic for the sub-oceanic climate (K 2 ), are present with 1.6% (3 species). Indicators of continental climate (K 4 ) are present with a low frequency (0.1% or 1 species). The mean value of this index is 2.9. Environmental analysis of the weed flora is in accordance with environmental requirements of cultivated species Solanum tuberosum (F 3 R 3 N 4 H 3 D 4 S-L 4 T 4 K 2 ), indicating an excellent adaptation of weed stands to the conditions of the potato production. 82

87 Ecological characteristics of ass. Panico-galinsogetum Tx. Et Beck in... From the aspect of environmental protection, particularly protection of the biodiversity, the study of biology and ecology of invasive (nonindigenous) species of weeds and their control in agrofitocenosis is very important (Vrbniĉanin et al., 2004, Stojanović et al., 2009). In observed stands fallowing invasive species were present: Ambrosia artemisiifolia, Xanthium strumarium, Galinsoga parviflora, Erigeron canadensis, Amaranthus retroflexus, Sorghum halepense and Portulaca oleracea. The presence of invasive species, reduces the number of indigenous species and adversely affects the biodiversity of this area. Spread of invasive species in natural ecosystems, distorts the ecological balance, changes the floristic composition and structure of phytocenosis. Connel (1995) emphasizes the importance of competitive abilities of potatoes in relation to the weeds present in the potato crop and their effect on yield and modification of existing measures of integrated protection. Integrated weed protection of potato crop consists of different methods for the suppression of weeds below the economical threshold, with the special consideration on the economical, ecological and toxicological conditions (Thakral et al., 1989, Blake, 2000). The knowledge of the biology and ecology of weeds and their communities is an essential prerequisite for the development of environmentally and economically acceptable concept of weed control in potato agrophytocenosis. 83

88 Ilić and Nikolić Plant species Table 1. Association Panico Galinsogetum Tx. et Beck Number of recordings Characteristic species of the association Panico Galinsogetum Tx. et Beck.. Panicum crus-galli L V 1235 Galinsoga parviflora Cav III 75 Characteristic species of the alliance Polygono-Chenopodion Koch em Sissingh Setaria glauca P.B III 120 Digitaria sanguinalis Scop II 15 Characteristic species of the order Chenopodietalia albi Tx., Lohm. et Prsg Amaranthus retroflexus L V 1360 Polygonum lapathifolium L IV 250 Solanum nigrum L IV 250 Chenopodium album L II 20 Capsella bursa-pastoris (L.) Med II 15 Sonchus oleraceus L I 10 Chenopodium hybridum L I 5 Characteristic species of the class Stellarietea mediae Tx., Lohm. et Prsg Sinapis arvensis L II 20 Stellaria media L II 15 Erigeron canadensis L I 10 Sonchus arvensis L I 10 Companions Bilderdykia convolvulus (L.) Dum V 230 Sorghum halepense L V 480 Convolvulus arvensis L V 395 DP CV 84

89 Ecological characteristics of ass. Panico-galinsogetum Tx. Et Beck in... Cirsium arvense (L.) Scop V 630 Polygonum persicaria L IV 300 Matricaria chamomilla L III 115 Agropyrum repens (L.) Beauv II 65 Ambrosia artemisiifolia L II 15 Matricharia inodora L II 60 Portulaca oleracea L I 10 Cynodon dactylon (L.) Pers I 10 Xanthium strumarium L I 10 Senecio vulgaris L I 5 Datura stramonium L I 5 Legend: DP - degree of presence, CV - cover value. 85

90 Ilić and Nikolić Conclusions Considering the results of the floristic, phytocenological and ecological analysis of weeds in conventional potato production, following conclusions can be made: In the research plots in vicinity of Beĉej, stands of the association Panico-Galinsogetum Tx. Beck et were found. Floristic composition of the association consists of 29 species. Two species have the greatest importance for the characterization of the community and its sintaxonomic characteristic, Panicum crus-galli and Galinsoga parviflora. Additionally, Amaranthus retroflexus, Cirsium arvense, Sorghum halepense, Convolvulus arvensis and Bilderdykia convolvulus have the important role in building up the cenobiotical relationships of the association. Specific characteristic of Panico-Galinsogetum association in the potato crop are the result of climatic and soil conditions and intensive use of chemical control measures. Analysis of environmental index values, obtained from the cover values, recorded weed flora indicates a moderately moist, neutral to slightly acidic medium, rich in nitrogen and nitrogen compunds, with high content of humus, well-aerated, nonsaline, with a favourable light and thermal regime, which corresponds with the temperate continental climate conditions. Among the recorded weed species 7 invasive (non-indigenous) species were present: Ambrosia artemisiifolia, Xanthium strumarium, Galinsoga parviflora, Erigeron canadensis, Amaranthus retroflexus, Sorghum halepense and Portulaca oleracea, whose expansion is necessary to be followed in the future. As a result of common agricultural practices and increasing use of herbicides, permanent changes in floristic composition and structure of crop weed communities are observed with the increase in the number of resistant weeds. The obtained results have a significant contribution to finding appropriate measures of reducing weed number in the agrophytocenosis of potato crop to the tolerant level, and at the same time to have a healthy produce, while preserving and protecting the environment. References AJDER, S. (1992): Uticaj dugogodišnje primene herbicida na sinmorfološke promene i sintaksonomski status korovske zajednice Panico Galinsogetum. Acta Biologica Jugoslavica, serija G: Acta herbologica, 1 (1):

91 Ecological characteristics of ass. Panico-galinsogetum Tx. Et Beck in... BLAKE, ANDREW ABEL, CHARLES, 2000: Weed control key to profits. Farmers weekly, ; 140 (10): 58. BRAUN-BLANKET J., 1964: Pflanzensociologie. Springer-Ferlag, Wien-New York. CONNEL, TIMOTHY RICHARD, 1995: Development of integrated weed and pest management strategies for potato (Solanum tuberosum L.). ProQuest Dissertations and Theses, 1995, p ĈANAK, M., PARABUĆSKI, S., BELIĆ, B., 1981: Uticaj sistema obrade na korovsku sinuziju agrofitocenoze. Matica srpska, Zbornik radova sa nauĉnog skupa Ekosistemi i mogućnost njihovog racionalnog korišćenja, ILIĆ, O., NIKOLIĆ, LJ., ILIN, Ţ., 2009: Asocijacija Panico-Galinsogetum Tx. Et. Beck pri konvencionalnoj proizvodnji krompira, XIV Savetovanje o biotehnologiji, Zbornik radova, Univerzitet u Kragujevcu, Agronomski fakultet, Ĉaĉak, Vol. 14. (15), JOSIFOVIĆ, M. (ed), ( ): Flora SR Srbije, 1-9, SANU, Beograd. JAVORKA, S., CSAPODY, V., 1975: Iconographie der Flora des Sűdostlichen Mitteleuropa. Akademiai Kiado, Budapest. KOJIĆ, M., MIŠOVIĆ, M., ŠINŢAR B., 1985: Prilog prouĉavanju korovske vegetacije krompira u zapadnoj Srbiji. Zavod za krompir Guĉa, Zbornik radova, sveska 4-5, KOJIĆ, M., STEPIĆ, R., ŠINŢAR, B., 1988: Korovska vegetacija Maĉve, Fragmenta Herbologica Jugoslavica, Vol. 17, No 1-2, , Zagreb. KOJIĆ M., MILIJIĆ, S., PETROVIĆ, R., LJILJAK, N., 1992: Korovska vegetacija kukuruza Timoĉke Krajine, Institut za poljoprivredna i tehnološka istraţivanja, Zajeĉar. KOJIĆ, M., POPOVIĆ, R., KARADŢIĆ, B., 1998: Sintaksonomski pregled vegetacije Srbije. Institut za biološka istraţivanja Siniša Stanković, Beograd. KOVAĈEVIĆ, D., MOMIROVIĆ, N., 2008: Uloga argotehniĉkih mera u suzbijanju korova u savremenim konceptima razvoja poljoprivrede, Acta Herbologica, Beograd, Vol. 17, No.2, MIŠOVIĆ M., ŠINŢAR, B., 1988: Prouĉavanje efikasnosti herbicida u usevu krompira, Treći kongres o korovima, Fragmenta herbologica Jugoslavica, Vol.16, (No 1-2), MIŠOVIĆ M., ŠINŢAR, B., BROĆIĆ, Z., ŠUŠIĆ, S., 1992: Ispitivanje efikasnosti herbicida na suzbijanje korova u usevu krompira u brdskom i ravniĉarskom podruĉju, Ĉetvrti kongres o korovima, Zbornik radova, Banja Koviljaĉa, NIKOLIĆ LJ., VUGA-JANJATOV, V., KNEŢEVIĆ, A., ŠEREMEŠIĆ, S., 2008: Floristiĉki sastav i ekološka analiza korovske sinuzije pšenice u uslovima plodoreda. Acta Biologica Jugoslavica, serija G: Acta herbologica, 17 (1): STEFANOVIĆ, L., 1984: Korovska vegetacija kukuruza severoistoĉne Srbije, Diss., Poljoprivredni fakultet, Beograd. STOJANOVIĆ, S., KNEŢEVIĆ, A., NIKOLIĆ, LJ., DŢIGURSKI, D., LJEVNAIĆ, B., 2009: Prisustvo adventivnih elemenata flore u biljnom pokrivaĉu formiranom u sistemu Mokra polja, Tematski zbornik radova Melioracije 09, Poljoprivredni fakultet, Novi Sad, ŠINŢAR, B., 1982: Korovska zajednica krompira u Juţnom Banatu. II Kongres zaštite bilja Jugoslavije. Vrnjaĉka Banja. ŠINŢAR, B., MIŠOVIĆ, M., ŠUŠIĆ S., BROĆIĈ, Z., 1988: Zakorovljenost i suzbijanje korova u usevu krompira Dragaĉeva, Fragmenta herbologica, 17Nº 1-2, THAKRAL, K.,K., PANDITA, M., L., KHURANA, S., C., KALLOO, G., 1989: Effect of time of weed removal on growth and yield of potato. Weed research, 1989 Feb1. TUTIN, G., HEYWOOD, V.H., BURGES, N.A., VALENTINE, D.H., WALTERS, S.M., WEBB, D.A. (ed.), ( ): Flora Europea, 1-5, University Press, Cambridge. 87

92 Ilić and Nikolić TÝR, Š., 2008: Actual Weed Infestation of Potato Crops in Slovakia, Acta Herbologica, Beograd, Vol. 17, No.2, VRBIĈANIN, S., KARADŢIĆ, B., DAJIĆ-STEVANOVIĆ, Z., 2004: Adventivne i invazivne korovske vrste na podruĉju Srbije, Acta Herbologica, Vol. 13, No. 1:

93 Herbologia Vol. 12, No. 1, 2011 TEMPORAL DYNAMICS OF INVASIVE WEED SPECIES IN THE SLOVAK REPUBLIC Štefan Týr, Tomáš Vereš, Jozef Smatana Department of Sustainable Agriculture and Herbology, Faculty of Agrobiology and Food Resources, Slovak University of Agricultural in Nitra, Trieda A. Hlinku 2, Nitra, Slovak Republic, Abstract In this study we summarized occurrence and temporal dynamics of three important invasive weed species, which infested field crops stands in the Slovak Republic. The study was realized in the years as a weed survey. Studied were: Abutilon theophrasti Med., Iva xanthiifolia Nutt and Sorghum halepense L. Very dangerous grassy weed species Sorghum halepense L. occurred only in the maize stands and on the stubbles after winter or spring cereals in the maize production region. Actual weed infestation with this species was only to 5% of acreage. Iva xanthiifolia Nutt and Abutilon theophrasti Med. occurred mainly in maize for grain, sugar beet and sunflower stands. We detected that the infestation with Abutilon theophrasti very significantly rises in the stands: maize for grain in the maize and sugar beet production region, sunflower in the maize production region, sugar beet in the maize and sugar beet production region. Weed infestation with Iva xanthiifolia rises very significantly in the sugar beet stands in maize and sugar beet production region. In the last five years of weed survey, Abutilon theophrasti became one of the most problematic weeds in the maize and sugar beet canopies. In the sunflower canopies, Iva xanthiifolia showed its rising tendency. Keywords: temporal dynamics, mapping, Sorghum halepense L., Abutilon theophrasti Med., Iva xanthiifolia Nutt. Introduction In the last few decades, ecologists and natural resource managers have recognized that the spread of non-native or alien organisms poses a serious threat to the conservation of natural and semi-natural habitats, and that such invaders can have a tremendous impact on the native faunal and floral communities. The spread of alien plants is a lasting and pervasive threat as the invaders proliferate and continue to spread, even if their introduction has ceased or ecosystems are not longer under the influence of disturbances and pollution. Indeed, the ever increasing number of alien species threatens our native diversity in many ways, and this threat is just an addition to other

94 Týr et al. threats caused by pollution, fragmentation and climatic change. The problem of biological invasions has become a central issue in the conservation of our biological diversity, and their control and management became costly and labour intensive (Jehlík, 1998; Pimentel, 2002). An alien species which becomes established in natural and semi natural ecosystems or habitats, is an agent of change, and threatens native biological diversity (McNeely, 2001). Thus, invasive plant species are distinguished from weed growing in agroecosystems or highly disturbed man-made habitats (Pysek, 1995; Richardson et al., 2000) Present study assessed the temporal dynamic of actual weed infestation of three dangerous invasive weed species Iva xanthiifolia Nutt., Abutilon theophrasti Med. and Sorghum halepense L. in the Slovak fields during the years Material and methods The assessment of the most dangerous weed species and their dynamic in canopy of winter oilseed rape was conducted at the Slovakia in The fields were selected in all production regions of Slovak Republic. An actual weed infestation was evaluated before preemergence application of herbicides. Screening of each field was made on 1 m 2 area with four replications. The four randomly established sample quadrants were situated minimally 20 m from field margin and apart from each other, respectively. The level of infestation was evaluated according to average density of weeds per square meter (Table 1). Obtained data from farms was statistically analysed by correlation analysis in Statistica 7.0. Table 1: Evaluation scale of actual weed infestation Actual weed infestation none Weak low medium heavy Group of weeds* Infestation level Number of weeds per m 2 Excessively dangerous Less dangerous Less important weed species according to checklist Hron Vodák, 1959, modified by authors 90

95 Temporal dynamics of invasive weed species in the Slovak Republic Table 2: Characteristic of evaluated production region of the Slovak Republic Characteristics Maize production region (MPR) Sugar beet production region (SBPR) Potato production region (PPR) Share of total arable land 24% 16.2% 18.9% Altitude up to 200 m up to 350 m m Average year temperature C 8-9 C C Average year precipitation mm mm mm Results and discussion One of the most dangerous invasive grassy weed in the Slovak Republic is Sorghum halepense L. It occurred only in the maize stands (Graph 1) and on the stubbles after winter or spring cereals in maize production region. Percentage of actual weed infestation with this species was only to 5% of acreage. But in Serbia S. halepense is dangerous grassy weed species in sugar beet stands (Konstantinović et al., 2006). In the last years Abutilon theophrasti Med. was dominant invasive weed species in the Slovakia. It occurred mainly in maize for grain, sugar beet and sunflower stands. But also stands of winter wheat, spring barley, winter oilseed rape and peas for grain were infected with this invasive species. In the last 16 years we have detected that the weed infestation with A. theophrasti very significantly rise in the stands: maize for grain in maize and sugar beet production region, sunflower in maize production region and sugar beet in maize and sugar beet production region (Table 3, Graph 1, Graph 2, Graph 3). In the last five years of weed survey became A. theophrasti one of the most problematic weed in the maize and sugar beet canopies. Abutilon theophrasti Med. is establishing itself in warmer regions as a weed of wide-row crops. The optimum environment for this species is in sugar beet stands, where in comparison with grass weeds, this broad-leaved weed overgrow and overshadow sugar beet and cause more damage (Konstantinović et al., 2001). Plants of A. theophrasti are very noticeable in sugar beet because of their height and leaf diameter. Biological characteristics predetermine this species to become a major late summer annual weed in our conditions. In the area of its origin, which is in middle Asia, it can be found as an arable weed mostly in cotton and soya. In central Europe it occurs more frequently since the 1980 s. In the Czech Republic is A. theophrasti a ruderal plant on places of its introduction (train stations, storage places) and only occasionally on arable land (South Moravia, lowlands of the Elbe river) (Jehlík, 1998; Soukup et al., 2004) 91

96 Týr et al. Iva xanthiifolia Nutt. occurred mainly in maize for grain, sugar beet and sunflower stands and also in the stands of winter wheat, spring barley, oat and winter oil seed rape. Weed infestation with Iva xanthiifolia rise very significantly in the sugar beet stands in maize and sugar beet production region (Table 3, Graph 2, and Graph 3). In the last five years in the sunflower canopies showed Iva xanthiifolia its rising tendency. Iva xanthiifolia is also as A. theophrasti a weed of wide row crops. It caused serious damages in sugar beet stands (Konstantinović et al., 2006) According to Tóth (2008) I. xanthiifolia and A. theophrasti reached the higher overpopulation rate and their control is at the higher economic importance in the Slovakia Sorghum halepense = *x *x^2 Iva xanthiifolia = 5.357E *x+0.133*x^2 Abutilon Theophrasti = E *x *x^2 Year:Sorghum halepense: r = ; p = ; y = *x Year:Iva xanthiifolia: r = ; p = ; y = *x Year:Abutilon Theophrasti: r = ; p = ; y = *x Year Sorghum halepense Iva xanthiifolia Abutilon Theophrasti Graph 1: Temporal dynamic of weed infestation with Sorghum halepense L., Abutilon theophrasti Med. and Iva xanthiifolia Nutt. in maize for grain stands in maize production region of Slovak Republic. 92

97 Temporal dynamics of invasive weed species in the Slovak Republic Table 3: Correlation coefficient of the most important weeds infestation level during years Abutilon theophrasti Med. Iva xanthiifolia Nutt. Sorghum halepense L. Maize for grain; VS NS NS MPR Maize for grain; VS NS - SBPR Maize for grain; NS NS - PPR Sunflower; MPR VS NS - Sunflower; SBPR NS NS - Sugar beet; MPR VS VS - Sugar beet; SBPR VS VS - Legend: VS very significant, NS non significant; MPR- maize production region, SBPR sugar beet production region, PPR potato production region Iva xanthiifolia = E *x *x^2 Abutilon Theophrasti = E *x *x^2 Year:Iva xanthiifolia: r = ; p = ; y = *x Year:Abutilon Theophrasti: r = ; p = ; y = *x Year Iva xanthiifolia Abutilon Theophrasti Graph 2: Temporal dynamic of weed infestation with Abutilon theophrasti Med. and Iva xanthiifolia Nutt. in sugar beet stands in maize production region of the Slovak Republic. 93

98 Týr et al. 120 Iva xanthiifolia = E *x *x^2 Abutilon Theophrasti = E *x *x^2 Year:Iva xanthiifolia: r = ; p = ; y = *x Year:Abutilon Theophrasti: r = ; p = ; y = *x Year Iva xanthiifolia Abutilon Theophrasti Graph 3: Temporal dynamic of weed infestation with Abutilon theophrasti Med. and Iva xanthiifolia Nutt. in sugar beet stands in sugar beet production region of the Slovak Republic. Conclusions In the last 16 years very significantly increased weed infestation of maize for grain, sunflower and sugar beet with Abutilon theophrasti Med. and because of this became A. theophrasti the most dangerous invasive weed species in the Slovak Republic. Infestation of field crops with this weed was in the last 5 years higher than 80% in sunflower and sugar beet stands and more around 50% in maize for grain stands. Infestation of the sugar beet canopies with Iva xanthiifolia Nutt. very significantly increased in maize and sugar beet production region. This weed infested around 40% of sugar beet acreage in the Slovak Republic in the last 5 years. Sorghum halepense L. was detected only in maize for grain stands in maize production region, but its occurrence was only rare. 94

99 Temporal dynamics of invasive weed species in the Slovak Republic Abutilon theophrasti Med. and Iva xanthiifolia Nutt. infested not only row crops but also stubbles after winter and spring cereals or winter oilseed rape. Acknowledgements: This paper was supported by VEGA project 1/0466/10 Adaptation of sustainable agriculture and mitigation of impact of climate change and VEGA project 1/0804/11 Research of sustainable agroecosystems, innovative technologies for production of bioproducts and their influence on human nutritional and health parameters. References JEHLÍK, V Alien expansive weeds of the Czech Republic and the Slovak Republic. Academia, Prague, Czech Republic, 1998, p. 506, ISBN KONSTANTINOVIĆ, B. MESELDŢIJA, M Zakorovljenost šeãerne repe i primena herbicida u sušnim uslovima sa osvrtom na problem perzistentnosti, XXII Seminar iz zaštite bilja, Novi Sad, KONSTANTINOVIĆ, B. MESELDŢIJA, M Occurrence, spread and possibilities of invasive weeds control in sugar beet. In: Proc. Nat. Sci., No. 110, 2006, pp MCNEELY, J.A The great reshuffling: human dimensions of invasive alien species. IUCN, Gland, Switzerland and Cambridge, UK, 2001, 242 p.. PIMENTEL, D Biological invasions: economic and environmental costs of alien plant, animal and microbe species. CRC Press, Boca Raton, 2002, 369 pp. PYSEK, P On the terminology used in plant invasion studies. In: PYSEK, P. PRACH, L. REJMÁNEK, M. WADE, M. (eds.) Plant invasions: general aspects and special problems. SPB Academic Publishing, 1995, pp RICHARDSON, D. PYSEK, P. REJMÁNEK, M. BARBOUR, M.G. PANETTA, F.D. WEST, C.J Naturalization and invasion of alien plants: concepts and definitions. In: Diversity and Distribution, vol. 6, 2000, pp SOUKUP, J. HOLEC, J. HAMOUZ, P. TYŠER, L Aliens on arable land. Scientific Colloquium, Weed Science in the Go, 2004, pp TÓTH, Š Weed occurrence under the field conditions of Slovakia. In. Acta fytotechnica et zootechnica, vol. 11, no.4, 2008, pp

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101 Herbologia Vol. 12, No. 1, 2011 WEED INFESTATION RESEARCH IN WINTER WHEAT FIELDS IN NORTHEAST BULGARIA Ganka Baeva, Ralitsa Nakova Plant Protection Institute, Kostinbrod, Bulgaria, Abstract The study was carried out in the in two agro - ecological regions of Northeast Bulgaria Dobrich and Silistra. The survey in different regions in Bulgaria was part of the national weed investigation. The estimation of weed density was taken according to density cover index (d.c.i) : 0 = none present; 1 = week degree of infestation (evaluated cover < 5%); 2 = average degree (5 25% ); 3 = high degree (25 50%); very high degree (50 100%). Out of the total 24 weed species on accordance with the Biological Classification adopted in our country, 10 winter-spring species in total were reported (9 of them broad-leaved and 1 grassy ones); 6 early spring species; 4 ephemeral weeds and 4 perennial species. The paper presents an analytical comment on the dynamics of weed infestation it also contains the arguments about the occurring short and longterm changes in weed associations. Key words: weeds, weed associations, density cover index, weed infestation, winter wheat Introduction Research of weed vegetation commonly is focused on the influence of numerous different factors (soil, climate, crop type, crop management, weed management).weed association are certain groups of weeds which develop according to agro-ecological conditions (Fisyunov, 1984). Weeds in Bulgaria embrace over 300 plant species pertaining to different biological groups (Kolev, 1963). The late - spring and winter spring species of the annual weeds are most common in the plain regions and those with creeping rootstocks and creeping roots of the perennials. The early spring species and the perennials predominate in the semi-mountainous and mountainous regions (Kolev, 1963; Delipavlov et al., 2003; Dimitrova et al., 2008). Compensation processes increasing a number of species have started in recent years. Weed investigation in hoed crops show an increase in the distribution of Echinochloa crus-galli, Setaria sp., Degitaria sanguinalis, and partly Amaranthus sp., Portulaca oleracea, Hibiscum trionum, and closegrown crops of Avena sp., Alopecurus myosuroides, Apera spica venti, Lolium sp., Anthemis sp., Galium tricorne, Galeopsis tetrachit, Bifora

102 Baeva and Nakova radians, Polygonum convolvulus (Pysek et.al., 2005; Milanova et.al., 2007; Baeva et. al., 2009 ). A tendency is noted in all crops and especially in perennial plantations towards increase in the density of weeds with creeping roots, mostly Convolvulus arvensis and Cirsium arvense and in weeds with creeping rootstocks, mainly Cynodon dactylon and Andropogon halepensis (Mander et al., 1999; Symic et al., 2003). Rational weed control conducted through an integrated system of measures conformed to the nature of weediness of the cultivated lands and the specific ecologic and economic conditions (Barberi, 2003). The objective of the present survey was to determine the distribution of annual and perennial weeds in different regions of Bulgaria. Material and methods The survey was carried out during and included both annual and perennial weeds in the wheat fields in two regions of Bulgaria Dobrich and Silistra. The observations were made on the 10% of cultivated land of wheat fields. The assessments were done on 10 randomly chosen plots. Recording was made by applying the diagonal method. (Dimitrova et.al., 2004). Life form of species were taken according to reference sources ( Kolev, 1963 ). In the region of Dobrich of 105 representative fields of winter wheat were assessed (10843 ha) in 2006 and 95 (11525 ha) in 2007 respectively. In the region of Silistra of 107 representative fields were assessed (14429 ha) in 2006 and 92 (12500 ha) respectively. The estimation of weed density was taken according to methodology (Table 1). All the plots were observed in the some area at the end of April, every year. KADIS is a Software for data base development, analysis including statistical and mapping of weed flora in Bulgaria. Table 1. Density cover index Density cover index (d.c.i) Degree of infestation Evaluated cover % 0 none 0 1 weak average high very high

103 Weed infestation research in winter wheat fields in northeast Bulgaria Result and discussion The density cover index occurrence of the most frequent annual and perennial weeds in the Dobrich region is given in Table 2. During in the wheat fields predominated by annual broadleaved weeds such as Veronika persica, Matricaria sp., Anthemis arvensis, Sinapis arvensis, Stellaria media, Viola tricolor, Bifora radians, Centaurea cyanus, Papaver rhoeas a d.c.i. from 2-3 or average to high degree infestation. On the other six weed species: Galium tricorne, Ranunculus arvensis, Polygonum convolvulus, Capsella bursa-pastoris, Delphinium consolida, Erodium cicutarium during the years on the survey, the degree of infestation was between week (d.c.i.- 1) and average (d.c.i - 2). The species diversity of weed infestation in other areas of the country tended to increase the types of weeds in wheat sowing (Milanova et. al, 2009). Of annual grass weeds, the most frequent are Avena fatua and Alopecurus myosuroides with degree of infestation, during 2006 and 2007, being weak and average respectively. There was a trend towards mass multiplication on this species. During 2007 another weed species as Lalium purpureum and Adonis aestivalis have appeared, but their density was only about 1-5%. The occurrence of twenty annual and four perennial weeds in the Silistra region is given in Table 2. During 2006 the percentage occurrence of four frequent broadleaved weed Matricaria sp., Galium tricorne, Anthemis arvensis, Sinapis arvensis is up to 50% ( d.c.i.- 3), but five and six weed species, it was up to 25% (d.c.i.- 2) and 5% (d.c.i.- 1) respectively. Of the annual grass weeds, the most frequent are Alopecurus myosuroides and Avena fatua during the period , being average ( d.c.i- 2). During 2007 in Silistra region, another weed species such as Polygonum convolvulus and Adonis aestivalis have appeared, but their density was only about 1-5%. In the wheat fields the frequent perennial weed species are Cirsium arvense, Convolvulus arvensis, Sonchus arvensis and Lepidium draba. During increased density of weed species such a Cirsium arvense and Convolvulus arvensis occurred up to 50% (d.c.i.- 3). A level of 25% infestation was average for Sonchus arvensis and Lepidium draba Widespread multiplication of two weeds Cirsium arvense and Convolvulus arvensis due to improper sowing treatments carried out mainly with disc harrowing the use of marginally effective herbicides against these types of weeds. 99

104 Baeva and Nakova Table 2. Frequency of annual and perennial weeds in wheat fields-region Dobrich and Silistra ( ) Weed species Dobrich Silistra Annual weeds Avena fatua L Alopecurus myosuroides L Veronica persica Gmel Matricaria sp Galium tricorne With Anthemis arvensis L Sinapis arvensis L Stellaria media L Ranunculus arvensis L Polygonum convolvulus L Capsella bursa-pastoris (L) Delphinium consolida L Viola tricolor L Papaver rhoeas L Bifora radians M.B Arabidopsis thaliana( L ) Centaurea cyanus L Erodium cicutarium L Lalium purpureum L Adonis aestivalis L Perennial weeds Cirsium arvense Scop Convolvulus arvensis L Sonchus arvensis L. Lepidium draba L (Valuation-cover index : 0 = none observed; 1 = weak; 2 = average; 3 = high; 4 = very high) Other types of widely occurring weeds belong to the group of resistant to herbicides on hormone (Papaver rhoeas, Anthemis arvensis, Galium tricorne). The use of these herbicides for years has helped to permanent change of weeds and these species have become among the most widespread. 100

105 Weed infestation research in winter wheat fields in northeast Bulgaria Conclusions During in the Dobrich and Silistra regions, the data from the survey shows that the most wide spread weeds in wheat fields are the annual ones. It was found that annual weeds predominated over the perennial species. Dominant involvement of winter-spring weeds sets high competition on wheat in the early growth stage of its development. These are among the most important and most plastic weeds in wheat in Bulgaria. There was a clear tendency to increase the areas and degree of infestation with perennial weeds Cirsium arvense and Convolvulus arvensis. The results obtained from the surveys suggest the need for planning differentiated weed control according to the degree in infestations. References BAEVA, G., R. NAKOVA, 2009: The weed flora in wheat fields in Bulgaria. Proceeding of IOBC EPRS, Kiev, BARBERI, P, 2003: Worldwide state and trends in research and weed management. Herbologia, 4. 1, 5-12 DELIPAVLO, D., I. CHESHMEDJIEV, M. POPOVA, D. TERSIISKI, I. KOVACHEV, 2003: Handbook of Bulgarian flora. Agricultural University, Plovdiv, 591pp. DIMITROVA, M., I JALNOV, ST. KALINOVA, T TONEV, S. MILANOVA, V. NIKOLOVA, G. BAEVA, R.NAKOVA, 2004: Methodology for recording and mapping of weeds in crop fields. Ministry of Agricultural and Forest, Sofia, 12 pp. FISYUNOV, A. B., 2004: Sornie rastenia. Moskva, 320 pp. KOLEV, I. 1963: Weeds in Bulgaria. BAS, Sofia, 566 pp. MANDER, U., M. MIKK., W. RULVIK, 1999: Ecological and low intensity agriculture as contributorsto landscape and biological diversity. Landscape and Urbon Planning, 46, MILANOVA, S., G. BAEVA, R. NAKOVA, S. MANEVA, L. CHAVDAROV, G. STOIMENOVA, T.VELICHKOVA, 2007: Some changes and trends in the weed communities in last years in Sofia region. Proceeding of the 9-th Symposium of flora of Southeastern Serbia and Neighbouring, Nis, MILANOVA, S. TS. DIMITROVA, M. VALKOVA, J. TACHKOV, L. ATANASOVA, L. ILIEVA, CH. CHRISTOV, 2009: Weed infestation of winter wheat in Pleven region, Bulgaria. Herbologia, 4, 1, 1-19 PYSEK, P., V. JAROSIK., Z. KROPAK, 2005: Effect of abiotic factors on species richness and cover in Central European weed communities. Agriculture, Ec0systems and Environment, 109, 1-8 SIMIC, M., L. STEFANOVIC, B. SINZAR, 2003: Seasonal changes of maize weed community in dependence of herbicide application and irrigation. Herbologia, 4. 1,

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107 Herbologia Vol. 12, No. 1, 2011 NEW SPECIES IN THE ALIEN FLORA OF MONTENEGRO Sead Hadţiablahović 1, Sulejman Redţić 2, Zlatko Bulić 1 1 Institute for the Protection of Nature of Montenegro, Podgorica, Montenegro, seadh@t-com.me 2 Faculty of Sciences, University of Sarajevo, Sarajevo, Bosnia and Herzegovina sredzic@pmf.unsa.ba Abstract The bibliography of alien plant taxa in Montenegro is not abundant. Only sporadic and, in many cases, accidental records concerning adventive/neophyte plant taxa exist. Terminology of alien (non-native) plant species in the present paper is taken from Pyšek et al. 2004, Taxon 53(1) ( Suggestions for a standardized terminology for alien plants ). According to the mentioned authors, alien plants can be divided according invasive status (casual, naturalised, invasive) and time of immigration (archaeophytes vs. neophytes). In the paper, a new invasive species recorded to the flora of Montenegro is Echinocystis lobata (Michx.) Torr. & Gray. The following taxa are reported as a new for the Montenegrin alien flora as a casuals: Acer saccharinum L., Narcissus polyanthos Loisel., Ocimum basilicum L., Jasminum nudiflorum Lindl. and Yucca gloriosa L.; a new naturalized alien species in Montenegro is Symphoricarpos albus (L.) S. F. All of introduced plant species, except Ocimum basilicum, are considered as neophytes. Introduction The bibliography of alien plant taxa in Montenegro is not abundant. While, for example, alien plant taxa in the countries of Central Europe were systematically recorded, in Montenegro only sporadic and, in many cases, accidental records concerning adventive/neophyte plant taxa exist. The most complete data on the flora of Montenegro are given in Prodromus Florae Peninsulae Balcanicae (Hayek, ), Conspectus Florae Montenegrinae (Rohlena, 1942). All the data dealing with the flora of Montenegro published from the year 1942 until the 2005 were compiled by Pulević (2005) in his work Građa za vaskularnu floru Crne Gore. The complete review on the investigation of flora and vegetation in Montenegro is given in the Bibliography compiled by Pulević (1980, 1985) and Pulević & Bulić (2004).

108 Hadţiablahović et al. In the recent time, many papers dealing, also, with an alien flora of Montenegro were made by many different authors: Aalto et al. (1972), Bulić (1994, 2009), Ĉernjavski & al. (1949), Hadţiablahović (2004, 2005, 2006, 2010), Hadţiablahović & Bulić (2004) Hadţiablahović et al. (2003, in press), Ivković (1982), Karaman (1997), Niketić (1998), Lakušić & Lakušić (1988), Lakušić et al. (2004), Petrović (2003, 2004), Pulević (1973, 1984,1976), Pulević & Mijušković (1977), Rakaj & Rostansky (2009), Stešević & Jovović (2005), Stešević & Jogan (2007a, 2007b), Stešević & Jovanović (2008a, 2008b), Stešević et al. (2008), Stešević & Drescher (2010), Stešević & Petrović (2010), Šmarda (1968), Vuksanović (2004). The aim of this study was to systematically review the latest data for alien flora of vascular plants in Montenegro, including taxonomic and chorological data. Material and methods The authors of plant names are abbreviated according to Rec. 46A of ICBN (McNeill et al. 2006), namely International Plant Names Index (2008, and according to Greuter et al , Tutin et al Consequently, we adopted the more recent terminology system proposed by Richardson et al. (2000) and elaborated by Pyšek et al. (2004a), which is based on a biogeographical and ecological approach, and we reviewed all the sources accordingly (see Table 1 for definitions). In order to identify the geographical provenance of the non-native species in the paper, we recorded the native distribution range for each taxon. Besides the main continental categories, i.e. Europe, Asia, Africa, North America, South America (including Central America) and Australasia (Hollis & Brummitt 1992), we used intercontinental groups, such as the Mediterranean, Eurasia and the Tropics, to include those species with extensive native distribution ranges across different continents, or whose provenance can not be determined more accurately. Table 1. Terminology adopted in the present paper (Pyšek et al. 2004). Non-native plants. (synonyms: alien, allocthonous, introduced, non indigenous, exotic, xenophytes) Plant taxa in a given area whose presence is due to intentional or unintentional human involvement. Casual plants. (synonym: not established) Alien plants that may flourish and even reproduce occasionally outside cultivation, but that eventually die out because they do not form self-replacing populations, and rely on repeated introductions for their persistence. 104

109 New species in the alien flora of Montenegro Naturalized plants. (synonym: established) Alien plants that sustain selfreplacing populations for at least 10 years, without the direct intervention of people, through the recruitment of seeds or ramets capable of independent growth. Invasive plants. A subset of naturalized plants that produce reproductive offspring, often in very large numbers and at considerable distances from the parent plants, and thus have the potential to spread over a large area. Archaeophytes. Alien plant species introduced before the year 1492, i.e. before the discovery of America by European colonizers. This date is conventionally rounded off to Neophytes. Alien plant species introduced after the year This date is conventionally rounded off to Results In the vascular flora of Montenegro have been identified and evaluated the following new alien species: Family: Aceraceae Species: Acer saccharinum L. (Syn.: Acer dasycarpum Ehrh.) Residence time: Neophyte; Invasion status: Casual; Native range: Canada & USA. Loc.: Podgorica-Block V, September 2009, leg. et det. S. Hadţiablahović. Family: Agavaceae Species: Yucca gloriosa L. Residence time: Neophyte; Invasion status: Casual; Native range: USA. Loc.: Podgorica-Kruševac, May 2009, leg. et det. S. Hadţiablahović, S. Redţić. Note: For the first time the species was recorded for Herceg Novi by Popović & Sterniša 1971: but only as an alien without the invasion status of the species. Family: Amaryllidaceae 105

110 Hadţiablahović et al. Species: Narcissus polyanthos Loisel. Residence time: Neophyte; Invasion status: Casual; Native range: SW Europe (France). Loc.: Podgorica-Stara Varoš, January 2011, leg. et det. S. Hadţiablahović. Family: Caprifoliaceae Species: Symphoricarpos albus (L.) S. F. Blake Residence time: Neophyte; Invasion status: Naturalized; Native range: Canada & USA. Loc.: Podgorica-Skaline, close to the river Moraĉa, May 2009, leg. et det. S. Hadţiablahović; Podgorica-Viseći most, close to the river Moraĉa, leg. et det. S. Hadţiablahović. Family: Cucurbitaceae Species: Echinocystis lobata (Michx.) Torr. et Gray. Residence time: Neophyte; Invasion status: Invasive; Native range: Canada & USA Loc.: Zaton, Valey of river Lim, right bank of the river, September 2007, leg. et det. S. Hadţiablahović. Family: Lamiaceae (Labiatae) Species: Ocimum basilicum L. Residence time: Archaeophyta; Invasion status: Casual; Native range: Tropical Africa. Loc.: Tuzi, June 2008, leg. et det. S. Hadţiablahović & Z. Bulić Family: Oleaceae Species: Jasminum nudiflorum Lindl. 106

111 New species in the alien flora of Montenegro Residence time: Neophyte; Invasion status: Casual; Native range: China. Loc.: Podgorica-Skaline, close to the river Moraĉa, May 2009, leg. et det. S. Hadţiablahović, S. Redţić. The identified plant species in continental regions still live in a culture. The only specis of Echinocystis lobata grows in natural habitats of flooded forests of alder, willow and poplar. A warmer climate is suitable for those species from culture to spread to other antropogenic habitats. Therefore, these species could be a good indicator of climate change monitoring. References AALTO M., HÃMET-AHTI L., RAUUHIJÃVI R., SUOMINEN J., TAARNA K., UOTILA M., UOTILA P. & VITIKAINENO O Jugoslavian retki VI (Botanical excursion to western Yugoslavia in VI. 1971, including a list of the collected vascular plants). - Helsingin Yliopiston kasvimuseon monisteita 5: 46 pp. BULIĆ Z Flora i vegetacija kanjona rijeke Cijevne u Crnoj Gori. (Magistarski rad - rukopis, Beograd). BULIĆ Z Flora i vegetacija kanjona rijeke Moraĉe u Crnoj Gori. (Doktorska disertacija - rukopis, Beograd). ĈERNJAVSKI P., GREBENŠĈIKOV O., PAVLOVIĆ Z O flori i vegetaciji Skadarskog podruĉja. - Glasn. Prir. Muz. Srpske Zemlje, Ser. B, Biol. Nauke 1-2: Beograd. GREUTER W., BURDET H. M. & G. LONG Med-Checklist 1, 3, 4. Geneve & Berlin. HADŢIABLAHOVIĆ S. ( ) The contribution to the flora of Montenegro. - Glas. Rep. Zavoda Zašt. Prir. (Podgorica) 27-28: HADŢIABLAHOVIĆ S. & BULIĆ Z. ( ) On distribution of some Balkan endemic and rare species in the Flora of Montenegro - Glas. Rep. Zavoda Zašt. Prir. (Podgorica) 27-28: HADŢIABLAHOVIĆ S Contribution to the flora of Montenegro and FR Yugoslavia. Hacquetia 4/1: HADŢIABLAHOVIĆ S. (2006). Floristic and chorological addition of the vascular flora of Montenegro. In Pešić V. & Hadţiablahović S. (Eds.) II International Symposium of Ecologists of the Republic of Montenegro. Book of Proceedings, Kotor. pp HADŢIABLAHOVIĆ S., KARAMAN V. & BULIĆ Z. (2003). Solanum eleagnifolium Cav. - a new neotophyt in the flora of Montenegro. II Congress of ecologists of the Republic of Macedonia, Ohrid. HADŢIABLAHOVIĆ S The Vascular flora of Ćemovsko polje (Montenegro). - Natura Montenegrina (Podgorica) 9(1): HADŢIABLAHOVIĆ S., REDŢIĆ S., BULIĆ Z. & TRAKIĆ S. Chorological additions to the flora of Montenegro. In press. HAYEK A Prodromus Florae Peninsulae Balcanicae. - Repert. Spec. Nov. Regni Veg. Beih. 30(1-3). 107

112 Hadţiablahović et al. HOLLIS S., BRUMMITT R. K World geographical scheme for recording plant distributions. Plant Taxonomic Database Standards No. 2 (Version 1.0). Available: de/tdwg/geo/default.htm. Accessed Nov, Pittsburgh: Hunt Institute for Botanical Documentation IVKOVIĆ O. (1982). Novi nalazi adventivne vrste Eleusine indica (L.) Gaertn (Poales, Poaceae) u Jugoslaviji. - Matica Srpska - Zbor. Prir. Nauke (Novi Sad) 63: KARAMAN V Flora istoĉnog dela Bokokotorskog zaliva (Magistarski rad, rukopis). Biološki fakultet (Beograd). LAKUŠIĆ D. & LAKUŠIĆ B Eleusine tristachya (Lam.) Lam. - In: Greuter, W. & Raus, Th.: Med-Checklist Notulae, 17. Willdenowia (Berlin), 28: LAKUŠIĆ D., STEVANOVIĆ V., BULIĆ Z., JOVANOVIĆ S., TOMOVIĆ G., VUKOJIĈIĆ S (2004). Floristical and Chorological contributions to the vascular flora of Montenegro - Glas. Rep. Zavoda Zašt. Prir. (Podgorica) 27-28: NIKETIĆ M Sporobolus indicus - In: Greuter, W. & Raus, Th.: Med-Checklist Notulae, 17. Willdenowia (Berlin), 28: PETROVIĆ D Chaenopofium multifidum & Medicago carstiensis two new species for the flora of Montenegro. - Third International Balkan Botanical Congress (Sarajevo), p. 70. PETROVIĆ D Flora planine Sutorman. (Magistarski rad, rukopis). Biološki fakultet (Beograd). POPOVIĆ, D. & STERNIŠA A Flora i vegetacija hercegnovskog podruĉja sa posebnim osvrtom na parkovsko bilje. Herceg Novi. PULEVIĆ V Prilog flori Crne Gore. - Glas. Rep. Zavoda Zašt. Prir. - Prir. Muz. (Titograd) 6: PULEVIĆ V Neke nove i rijetke vrste u flori Crne Gore. - Glas. Rep. Zavoda Zašt. Prir. - Prir. Muz. (Titograd) 9: PULEVIĆ V Bibliografija o flori i vegetaciji Crne Gore. CANU. Titograd. PULEVIĆ V Euphorbia prostrata Aiton, nova adventivna vrsta u flori Jugoslavije. Drugi kongres o korovima (Osijek): PULEVIĆ V Dopuna bibliografiji o flori i vegetaciji Crne Gore - Glas. Rep. Zavoda Zašt. Prir. - Prir. Muz. (Titograd) 18: PULEVIĆ V GraĊa za vaskularnu floru Crne Gore. - Rep. Zavod Zašt. Prir. (Podgorica), posebna izdanja, Knjiga 2. PULEVIĆ V. & MIJUŠKOVIĆ M. (1977). Korovska flora na nasipu ţeljezniĉke pruge preko Skadarskog jezera. Jugosl. Sav. Herb. Ţeljez. (Zagreb): PULEVIĆ V. & BULIĆ Z Bibliografija o flori i vegetaciji Crne Gore (druga dopuna) - Rep. Zavod Zašt. Prir. - Podgorica (posebno izdanje). PYŠEK P., RICHARDSON M. D., REJMÁNEK M., WEBSTER L. G., WILLIAMSON M. & KIRSCHNER J Alien plants in checklists and floras: towards better communication between taxonomists and ecologists. Taxon 53(1): RAKAJ M. & ROSTANSKY K New species of the genus Oenothera L. from the coasts of Albania and Montenegro. Natura Montenegrina, Podgorica, 8(3): RICHARDSON D. M., PYŠEK P., REJMÁNEK M., BARBOUR M. G., PANETTA F. D., WEST C. J Naturalization and invasion of alien plants: Concepts and definitions. Divers. Distrib 6: ROHLENA J Conspectus Florae Montenegrinae. Preslia STEŠEVIĆ D. & JOVOVIĆ Z Sycios angulatus - a new non-indigeous species in the flora of Montenegro. Herbologia vol. 6(3):

113 New species in the alien flora of Montenegro STEŠEVIĆ D. & JOGAN N. 2007a. Two new neotophytes in the of Flora of Montenegro: Artemisia verlotiorum and Sporobolus vaginiflorus - Natura Montenegrina (Podgorica) 5: STEŠEVIĆ D. & JOGAN N. 2007b. Addition to the Flora of Montenegro: Setaria verticilliformis Dumort., Setaria viridis (L.) PB subsp. pycnocoma (Steud.) Tzvel., Impatiens balsamina L. and Catalpa bignonioides Walt. - Natura Montenegrina (Podgorica) 6: STEŠEVIĆ D. & JOVANOVIĆ S. 2008a. Contribution to the knowledge of nonindigenous flora of Montenegro. In Terzić S. (ed.), Proceedings of the Workshop devoted to 25 th Anniversary of the Faculty of Sciences and Mathematics at University of Montenegro: Contemporary mathematics, physics and biology - University of Montenegro, pp STEŠEVIĆ D. & JOVANOVIĆ S. 2008b. Flora of the city of Podgorica, Montenegro: taxonomic analysis. Arch. Biol. Sci. 60(2): STEŠEVIĆ D., JOVANOVIĆ S. & ŠĆEPANOVIĆ S Flora of the city of Podgorica, Montenegro chorologic structure and comparison with the floras of Rome, Patras, and Salonika. Arch. Biol. Sci., Belgrade, 61 (2), STEŠEVIĆ D., PETROVIĆ D., BUBANJA N., VUKSANOVIĆ S., BIBERDŢIĆ V Contribution to the Flora of Montenegro (Supplementum to the Material of the Vascular Flora of Montenegro). - Natura Montenegrina (Podgorica) 7(3): STEŠEVIĆ D. & DRESCHER A Addition to the vascular Flora of Montenegro (new taxa and new records). - Natura Montenegrina (Podgorica) 10(1): STEŠEVIĆ D. & PETROVIĆ D Preliminary list of plant invaders in Montenegro. - Biologica Nyssana. 1(1-2): Niš. Serbia. STEVANOVIĆ V., NIKETIĆ M., JOVANOVIĆ S., LAKUŠIĆ D. & BULIĆ Z. ( ) Novi taksoni za vaskularnu floru Durmitora. - Bull. Inst. Bot. Univ. (Beograd) 24-25: ŠMARDA J Výsledky biogeografických cest do Jugoslávie v letech Ĉeskosl. Akad. Ved Geogr. Ústav. (Brno). TUTIN T. G., HEYWOOD V. H., BURGES N. A., MOORE D. M., VALENTINE S. M. & D. A. WEBB , Flora Europaea 1-5, 1 (ed. 2). University Press, Cambridge. VUKSANOVIĆ S Flora planine Babiji zub (Magistarski rad, rukopis). Biološki fakultet (Beograd). 109

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115 Herbologia Vol. 12, No. 1, 2011 DISTRIBUTION OF TREE OF HEAVEN SPECIES Ailanthus altissima (Mill.) Swingle IN HERZEGOVINA Danijela Petrović 1, Nevenko Herceg 1, Zlatko Kovačević 2, Ivan Ostojić 1 1 Agronomski i prehrambeno-tehnološki fakultet Sveuĉilišta u Mostaru; mail: petrovic.danijela@tel.net.ba 2 Poljoprivredni fakultet Univerziteta u Banjoj Luci Summary Based on the authors' research in progress in recent years the distribution of neophyte species Ailanthus altissima (Mill.) Swingle in Herzegovina, we conclude that species spread and domesticated in the region of Herzegovina. Considering that the tree of heaven is invasive species, it is need to pay attention to the prevention of further spread and reduce the number of already existing populations. Priority should be given to those actions which are environmentally friendly. Introduction Tree of heaven, Ailanthus altissima (Mill.) Swingle was adopted from Southeast Asia. In Europe it was introduced (in London) in as an ornamental plant. It very quickly established itself on all continents except Antarctica. Today is one of the most aggressive plant species. Species is relentlessly expanding, changing the landscape and pushing them endanger the survival of autochthonous plant species. It is highly aggressive, invasive and adaptable species that grows in different soil types, and just do not tolerate excess water and deep shade. It is found in different places from urban areas to difficult reaching places. It is daptable to all conditions (salt, pollution, heat, drought). The aim of paper is to show the distribution of Ailanthus altissima (Mill.) Swingle in Herzegovina, which is based on research of numerous authors over a long period of time. Materials and methods In research are used published data and data resulting from field research of authors of this paper. Field studies were conducted during 2008, 2009, in the area of Herzegovina. Collected material was stuffed and put into a collection of Agronomy and Food Technology Faculties, University of Mostar.

116 Petrović et al. Results and discussion Below is a list of collected data of Ailanthus altissima (Mill.) Swingle sites, which can be used for mapping of this species range. The largest presence of tree of heaven is a registered along the major routes leading from: - Neum to Ravno-Hrasno-Chair-Ĉapljina-Mostar-Jablanica-Konjic - Ljubuski-Gruda-Posušje - Mostar-Siroki Brijeg-Posušje-Tomislavgrad (lower prevalence) The southernmost site is in Neum (Dubrovnik to exit). Along the main road M17 species is present in sites Draĉevo, Višići, Ĉeljevo, Klepci, tree of heaven is in small groups. It is registered in the Park Hutovo mud (Sjekose, Svitava). In the area of Poĉitelj, Ševas njiva, Buna, Mostar airport, larger population of tree of heaven are recorded. In the city of Mostar, along the entire main communication - Bulevar, in places where are ruins, on parking lots, abandoned green areas larger populations of tree of heaven are present, over the age of 5 years. With river flows Bregava, Buna, Bunica, Radobolja, Krupa, Jasenice, Vrioštice, Dreţanke, Neretva, tree of heaven is in small groups combined with acacia and willow. Tree of heaven is a species that is easily adapted to any habitat. It belongs to the group of the most tolerant species. Natural climate of tree of heaven in terms of annual rainfall is less favorable than for us. Annual rainfall rarely goes over 600 mm and there are also areas of 400 mm and below. This amount is distributed unevenly, around 90% coming in summer period of year. It is understandable when one takes into account that this species are grown well in our region and it is often used for afforestation. In the Mediterranean and sub-mediterranean zone of the Federation of Bosnia and Herzegovina is the largest distribution of tree of heaven. Tree of heaven with its invasiveness makes a lot of pressure on native plants and biodiversity of areas and thus pose the greatest threat to the karst area of Bosnia. The tendency of further expanding of tree of heaven is primary relates to submediterranean area where are can be expected significant damage from this invasive species. Study in Germany has shown that tree of heaven growing in 92% of cases in densely populated areas of Berlin, 25% in the suburbs, and only 3% outside the city in general. Indeed, our results showed that tree of heaven is mainly located in urban areas. 112

117 Distribution of tree of haven species Ailianthus altissima (Mill.) swingle in... Fig 1. Ailanthus altissima 113

118 Petrović et al. Conclusion Tree of heaven has been named the "tree from hell" because of its invasiveness, spread and difficulty in its eradication. It is a highly aggressive species and is the biggest threat to the karst area of Bosnia. Endangers nearly all habitats. It is widespread and has put pressure on the native flora and overall biodiversity of the area. Based on research by the group of authors, we can conclude that this species spread and domesticated in most parts of Herzegovina. Literature BURCH P.L., ZEDAKER S.M Removing the invasive tree Ailanthus altissima and restoring natural cover. Journal of Arboriculture, 29(1): CACHON, D L arbre du ciel (Ailanthus altissima) Histoire et biologie, Autoédition, Nogent-sur- Marne DE FEO, V.; MANCINI, E.; VOTO, E.; CURINI, M.; DIGILIO, M. 2009, Bioassay-oriented isolation of an insecticide from Ailanthus altissima. Journal of Plant Interactions, 4, 2, GOVER A., KUHNS L., JOHNSON J Managing tree of heaven (Ailanthus altissima) on roadsides. Roadside vegetation management. Factsheet 3, 4p. http//rvm.cas.psu.edu GRAVANO E., GIULIETTI V., DESOTGIU R., BUSSOTTI, F., GROSSONI P., GEROSA G., TANI, C Foliar response of an Ailanthus altissima clone in two sites with different levels of ozone-pollution. Environmental Pollution, 121(1): hal , version 1-14 Apr 2010 HOSHOVSKY M.C The nature conservancy. Element Stewardship Abstract For Ailanthus altissima. ISAJEV, V., BEUS, V., MATARUGA, M. (2006): Biodiverzitet zaštićenih podruĉja u Bosni i Hercegovini i njihov znaĉaj za konzervaciju. Nauĉna konferencija: Gazdovanje šumskim ekosistemima nacionalnih parkova i drugih zaštićenih podruĉja, Jahorina - NP Sutjeska, Zbornik radova: KNAPP, L. B., CANHAM C.D Invasion of an old-growth forest in New York by Ailanthus altissima: sapling growth and recruitment in canopy gaps. Journal of the Torrey Botanical Society, 127:

119 Herbologia Vol. 12, No. 1, 2011 CLIMATE CHANGE AND WEEDS IN HUNGARY Gabriella Kazinczi Kaposvár University, Department of Botany and Plant Production, H-7400 Kaposvár, Guba S. str. 40, Hungary Abstract The change of weed flora on arable land has been continuously followed in Hungary for more than 60 years. Based on the results of the Five National Weed Surveys carried out in Hungary between 1947 and 2008, we searched relation between the climate change and dominance of weed species. Weed species surveyed in maize in late summer were analyzed based on their gene centre, requirement for temperature and water. Majority of the surveyed weed species were indifferent to temperature (T0) and mesophyte (W2). Cosmopolitan elements were dominant considering cover % with a proportion of 45-60%. During the First National Weed Survey, cosmopolitans were followed by Eurasian elements. Since the Second National Weed Survey the cover percent of adventive elements considerably exceeds that of Eurasian elements and their importance greatly enhanced with time. It has been concluded that climate change is only one, but not the most important factor responsible for the change of weed flora in Hungary. Key words: climate change, weed flora, weed surveys, maize Introduction Climate change (global warming) is a factor, influencing all parts of the life. Physiological processes of plants are greatly influenced by the enhanced temperature and carbon dioxide concentration in the atmosphere and extremity of meteorological factors. Safety of agriculture, including food supply, is most susceptible to changing climate and extremity of weather (Láng et al., 2007; Babinszky et al., 2010). The change of weed flora on arable land has been continuously followed in Hungary for more than 60 years. Analyzing the database of weed surveys important relations between weed flora and global warming could be observed (Novák et al., 2009, Kazinczi, 2009). Weed species showing a times increase in their cover percent in the last 60 years, all belong to thermophilous ones. Their area (tropical, subtropical, Mediterranean gene centres) spreads towards north (Szőke, 2001). In this work the weed species surveyed in maize in late summer were analyzed based on some ecological indicator values (water and temperature requirements) and gene centres.

120 G. Kazinczi Materials and methods There were five national weed surveys carried out between 1947 and 2008 in Hungary. Vicinities of 202 settlements were selected including all soil types important for the arable plant production. Regarding that winter wheat and maize production are traditions in Hungary (both of them are grown on around 1 million hectares) surveys had to be done in maize and wheat crops and on wheat stubbles. In order to compare the results of weed surveys carried out at different times, the methods and locations of the surveys did not change. The cover percentages of the weed species were determined and beside these, the plant phenological stages and GPS coordinates of the sample squares were also recorded (Novák et al., 2009). In order to analyze weed species surveyed in maize in late summer in respect to their requirement for water, the following indicator values were used (modified after Borhidi, 1995): W1 (according to Ellenberg scale 0, 1, 2, 3) plants of dry habitats, xerotolerant species W2 (according to Ellenberg scale 4, 5, 6) mesophytes W3 (according to Ellenberg scale 7, 8) plants of wet soils W4 (according to Ellenberg scale 9, 10, 11) water plants (hygrophytes) For analyzing weed species in respect to their requirement for temperature, the following indicator values were used (Soó, 1973): T0: indifferent to temperature T1: high cold tolerance (arctic, alpine) T2: cold tolerance T3: less cold tolerance T4: thermophilous, cold susceptible T5: highly thermophilous (mediterranean, pontus) Grouping of the weed species according to their gene centres the works of Hortobágyi (1968, 1986), Soó (1973), Simon (1992) and Horváth et al. (1995) were used. The flora elements (gene centres) were the following: adventive (ADV), alpin (ALP), Atlantic-submediterranean (ASM), Balkan (BAL), Carpathian endemism (CAR), Central-Asian (CEA), Central- European (CEU), circumpolar (CIR), continental (CON), Eurasian (EUA), European (EUR), cosmopolitan (KOZ), mediterranean (MED), Pannonianbalkan (PAB), pannon (PAN), pontus-mediterranean (POM), pontus (PON), pontus -pannonian (POP), submediterranean (SME), East-submediterranean (SMO), turanian (TUR). 116

121 Climate changes and weeds in Hungary Results and discussion Analysis of weed species according to their requirement of water Irrespectively from the surveyed periods the proportion of the mesophytes is the highest and the proportion of the hygrophytes is the lowest. Number of xero-tolerant species is higher as compared to their cover %, while the contribution of W3 species to the cover percent is higher than their proportion to the whole species number. No significant changes are observed during the experimental period (between 1950 and 2008) (Table 1, Figure 1). Table 1. Distribution of weed species based on their relative moisture figures in maize surveyed in late summer Relative moisture figures 1 W1 Time of National Weed Surveys Weed species Cover (%) 5,6789 2,2501 2,4692 2,6828 5,1405 W2 Weed species Cover (%) 27,759 23, , , ,2202 W3 Weed species Cover (%) 4,4353 8, ,2626 9, ,917 W4 Weed species Cover (%) 1,5546 0,2475 0,4517 0,503 0,7288 Total species number Total cover 39, , , , , relative moisture figures Analysis of weed species according to their requirement of temperature Weed species belonging to T3 and (T0) relative temperature figures are dominant considering the weed species number and cover %, respectively. Proportion of T1 species is very low and T5 species do not occur at all. Species number and cover percent of T2 species continuously increased in the last 60 years but in a small degree, while unambiguous tendency could not be observed in respect to T4 (thermophilous) species (Table 2). Proportion of T0 and T3 species is the highest in maize surveyed in late summer, followed by T4 and T2 species. Species indifferent to temperatures (T0 relative temperature figure) had the biggest proportion from 117

122 cover (%) species (%) G. Kazinczi the total cover percent, except during the First National Weed Survey. Cover proportion of T3 species decreased since the Second National Weed Survey by 48-75%. Cover proportion of T2 and T4 species is much more lower, than their proportion from the total species number (Figure 2) w1 w2 w3 w w1 w2 w3 w4 Fig. 1. Distribution of weeds species based on their relative moisture figures in percentage of the total species (up) and in percentage of the total cover (down) Analysis of weed species according to flora elements (gene centres) Eurasian flora elements - in percent of total species number - are dominant, followed by cosmopolitan and adventive elements. Proportion of submediterranean species is around 6.5% and do not change considerably with time. Contribution of Mediterranean, pontus, pontus mediterranean and pontus pannon elements is less, it varies between 0.77 and 4.28%, and their proportion generally decreases with time. Proportion of circumpolar, continental and Central-European elements is between 6.2 and 1%, their values do not change considerably with time (Figure 3). 118

123 Climate changes and weeds in Hungary Table 2. Distribution of weed species based on their relative temperature figures in maize surveyed in late summer Relative Time of National Weed Surveys temperature figures T0 Weed species Cover (%) 16,472 22, , , ,2851 T1 Weed species Cover (%) 0,0008 0,0106 0,0031 0,0006 0,0045 T2 Weed species Cover (%) 0,5003 0,5201 0,9527 1,1742 1,3862 T3 Weed species Cover (%) 21, ,7015 9,2249 9, ,7847 T4 Weed species Cover (%) 1,1312 0,5383 0,6837 0,9657 1,4456 T5 Weed species Cover (%) Total species number Total cover 39, , , , , relative temperature figures Cosmopolitan elements are dominant considering cover % with a proportion of 45-60%. During the First National Weed Survey cosmopolitans are followed by Eurasian elements. Since the Second National Weed Survey the cover percent of adventive elements considerably exceeds that of Eurasian elements and their importance enhance with time. Cover percent of adventive elements increased nearly five times during the Fifth National Weed Survey as compared to the First National Weed Survey. Contribution of Eurasian elements to total cover decreased with time. Cover proportion of other flora elements is much more lower, than proportion of Eurasian and adventive elements (Figure 4). It can be concluded that majority of weed species surveyed in maize in late summer belong to mesophytes and T0 relative temperature figure (indifferent to temperature). Dominance of neither xero-tolerant nor thermophilous species could be observed in time. Other sources reported the same (Kazinczi et al., 2004, Kazinczi, 2009). 119

124 Cover % % species % % G. Kazinczi T0 T1 T2 T3 T T0 T1 T2 T3 T4 Fig. 2. Distribution of weeds species based on their relative temperature figures in percentage of the total species (up) and in percentage of the total cover (down) No close correlation is observed between the distribution of weeds and meteorological factors induced by global warming (high temperature, drought). Climate change is only one but not the most important factor influencing the change of weed flora. Other factors, like selection pressure of herbicides, monoculture and other cropping practices, changes in the ownerships of agricultural plots, changes in the biological characteristics of weeds (e.g. appearance of herbicide resistant biotypes) and level of plant production (extensive, intensive) also play very important role in this respect. 120

125 species % % Climate changes and weeds in Hungary ADV ALP ASM CAR CEA CEU CIR CON EUA EUR KOZ MED PAB PAN POM PON POP SME SMO TUR Fig. 3. Proportion of weed species surveyed in maize in late summer based on the gene centres in percentages of total species number 121

126 cover % G. Kazinczi ADV ALP ASM CAR CEA CEU CIR CON EUA EUR KOZ MED PAB PAN POM PON POP SME SMO TUR Fig. 4. Proportion of weed species surveyed in maize in late summer based on the gene centres in percentages of total cover percent 122

127 Climate changes and weeds in Hungary References BABINSZKY, L.,DUNKEL, Z., TÓTHI, R., KAZINCZI, G., NAGY, J. (2011): The impacts of climate change on agricultural production. Hungarian Agricultural Research, in press. BORHIDI, A. (1995): Social behaviour types, the naturalness and relative ecological indicator values of the higher plants in the Hungarian flora. Acta Botanica Hungarica 39: HORTOBÁGYI, T. (1968): Botany 2. Plant taxonomy and plant geography. Tankönyvkiadó, Budapest (in Hungarian). HORTOBÁGYI, T. (1986): Agrobotany. Mezőgazdasági Kiadó, Budapest (in Hungarian). HORVÁTH, F., DOBOLYI, Z., MORSCHAUSER, T., LŐKÖS, L., KARAS, L., SZERDAHELYI, T. (1995): FLORA database. MTA-ÖBKI, Vácrátót. KAZINCZI, G. (2009): The role of global warming in the change of weed flora in Hungary. Climate change: challenge for training of applied plant scientist, Martonvásár pp KAZINCZI, G., REISINGER, P, MIKULÁS, J. (2004): The effect of climatic changing on herbology. Hungarian Weed Research and Technology 5 (2): LÁNG, I., CSETE, L., JOLÁNKAI, M. (eds.) (2007): Global climate change: Hungarian effects and responses. VAHAVA report. Szaktudás Kiadó Ház, Budapest (in Hungarian). NOVÁK, R., DANCZA, I., SZENTEY, L., KARAMÁN, J. (2009): Arable Weeds of Hungary. Fifth National Weed Survey ( ). Ministry of Agriculture and Rural Development, Budapest SIMON, T. (1992): Plant identification book. Tankönyvkiadó, Budapest (in Hungarian). SOÓ, R. (1973): Plant taxonomical and plant geographical handbook of Hungarian flora and vegetation. Akadémiai Kiadó, Budapest (in Hungarian). SZŐKE, L. (2001): Relation between rapid spread of thermophilous weeds and climate change. Növényvédelem 37: (in Hungarian). 123

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129 Herbologia Vol. 12, No. 1, 2011 ALLELOPATHIC EFFECT OF ABUTILON THEOPHRASTI Med. ON LETTUCE, CARROT AND RED BEET Natalija Galzina, Maja Šćepanović, Matija Goršić, Ivana Turk* Department of Herbology, Faculty of Agriculture, University of Zagreb, Svetosimunska 25, Zagreb, Croatia, *Student of the Faculty of Agriculture, University of Zagreb Abstract Velveatleaf (Abutilon theophrasti Med.) is present for a long time in Croatia, but as a weed in agriculture is known since 1980's. Last few years velvetleaf spreads very fast and uncontrollably. It is mostly distributed in the continental part of the country but recently it is also found in coastal areas. Besides competitive abilities it also has allelopathic potential. In this study the aqueous extract of velvetleaf was prepared from mature capsule with seeds to investigate the effect of velvetleaf on germination, and the length of radicle and shoot of three test plants: lettuce, carrot and red beet. Germination inhibition was significant only in carrot (41.2%,) while the reductions of the length of radicle were significant for all test plants. Velvetleaf inhibited the length of radicle in carrot by 83.8%, in red beet by 49.4% and lettuce by 37.4%. Length of shoot was significantly reduced in carrot (88.1%) and red beet (66.4%). Keywords: Velvetleaf (Abutilon theophrasti Medik.), allelopathy, lettuce, carrot, red beet Introduction Abutilon theophrasti is an invasive plant species in Croatia and one of the most important weed species from Malvaceae family (Novak, 2007). First data about its presence in Croatia were published in (Schlosser and Farkaš-Vukotinović, 1869), and Šulek in Although velvetleaf is present for a long time in Croatia, as a weed in agriculture is known since 1980 s and especially after mid 1990 s (Novak, 2007). Velvetleaf is distributed in continental part, from east to Karlovac but recently is more often found in coastal parts of Croatia (Novi Vinodolski, Matulji, Poreĉ, Imotski, Ploĉe, valley of river Neretva). Last few years velvetleaf spreads very fast and uncontrollably in Croatia (Flegar and Novak, 2005). It appears in big populations and sometimes with more than 200 individual plants per square meter. It is more often present in crops than as a ruderal weed (Novak, 2007). Velvetleaf is a troublesome weed in numerous row crops, especially corn, soybean, sugar-beet, potato, sunflower and onion (Novak, 2007). Many

130 Galzina et al. studies have reported decreases in crop yield due to competition from A. theophrasti. Velvetleaf is efficient under conditions of low sunlight. It grows well when partially shaded and can complete its life cycle even under a crop canopy (Mitich, 1991). When emerging simultaneously with corn, velvetleaf can surpass corn growth by the end of the season, develop a layer of leaves above the corn canopy and, therefore, interfere with crop light interception (Sattin et al. 1992). Besides competitive abilities it also has allelopathic potential which inhibits germination and emergence of concurrent plants. Rice in defines allelopathy as any direct or indirect effect by one plant, including micro-organisms, on another through the production of chemical compounds that escape into the environment and subsequently influence the growth and development of neighboring plants. IAS in extended definition as any process involving secondary metabolites produced by plants, algae, bacteria and fungi that influences the growth and development of agricultural and biological systems (in Novak, 2007). Allelopathic effects of different weed species on cultivated plants, mainly arable crops, are topic of numerous research studies. In Croatia, Novak (2007) confirmed the inhibitory allelopathic effect of velvetleaf root extract, stem extract and leaf extract on the length of radicule of oilseed rape, soybean and winter oat. On the other side, the same extracts diluted with water in ratio 1:2 stimulated the length of oilseed rape shoot. Author did not determine any allelopathic effect of velvetleaf on sunflower and popcorn. Kazinczi et al. (2004) note that sunflower fresh weight was reduced by water extract of velvetleaf root, while shoot extract did not influence the fresh weight of sunflower. Šćepanović et al. (2007) confirmed the velvetleaf inhibitory effect on radicle, shoot and germination of corn. Effect of velvetleaf on vegetable crops is less investigated. Therefore, the aim of this paper was to determine the allelopathic effect of velvetleaf on lettuce, carrot and red beet. Materials and methods Allelopathic effects of velvetleaf were investigated in a laboratory of the Faculty of Agriculture, University of Zagreb in May Aqueous extract of velvetleaf was prepared from mature capsule with seeds which were powdered by mixer and diluted in distilled water in ratio: 50 g of powdered plant material on 5 dl of distilled water and kept at room temperature. After 24 hours, plant material was removed and extract was filtered. In sterilized Petri dishes (100 mm x 20 mm) wetting of two filter paper layers with 5 ml of prepared extract was done. In each Petri dish 25 seeds of individual test plant were sowed, in four replicates. Research also 126

131 Allelopathic effect of Abutilon theophrasti Med. on lettuce, carrot and red beet included untreated control, wetted with 5 ml of distilled water. Test plants were lettuce, carrot and red beet. After sowing Petri dishes were placed in plastic bags in dark at room temperature (25 o C) to germinate. Time of evaluation depended on test plant velocity of germination and was between five to seven days. Allelopathic effects were obtained through following values: % of germination, length of test plant ridicule, length of test plant shoot. Length of lettuce radicle and shoot was measured five days after sowing, and measurement for carrot and red beet was done seven days after sowing. Results and discussion As shown in Table 1. aqueous velvetleaf extract had a significant effect on the development of all test plants. Table 1. Effect of velvetleaf extract on the length of test plant radicule and shoot and germination Test plant Treatment Germination Length of Length of (%) radicle (cm) shoot (cm) Lettuce Untr ABUTH 97.0 n.s * n.s. Carrot Untr ABUTH 40.0* 0.283* 0.216* Red beet Untr ABUTH 77.0* 0.710* 0.467* Untr.- untreated control, ABUTH-aqueous velvetleaf extract n.s.-not significant; *-significant difference at P=0.05 Velvetleaf significantly inhibited the germination of carrot and red beet while it did not have any effect on lettuce germination. The length of test plants radicle and shoot was significantly reduced in all test plants, but especially in carrot inhibiting the length of radicle six times and even nine times the length of shoot compared to the control. 127

132 Inhibition (%) Galzina et al ,8 88, , ,2 37,4 49,4 Lettuce Carrot Red beet ,3 7,7 3 Germination Length of radicule Length of shoot Graph 1. Inhibition of germination and length of the test plant radicle and shoot On Graph 1. is shown the inhibition of germination, length of radicule and shoot of all test plants compared to control. As shown, carrot was the most susceptible test plant on velvetleaf presence. The germination of carrot seeds was the most inhibited (41.2%), while the effect of aqueous velvetleaf extract inhibited red beet germination by 16.3%. Velvetleaf did not show significant inhibitory effect on lettuce germination. Compared with untreated control the average length of radicle in all test plants was significantly reduced. Carrot radicle was the most reduced by 83.8% (Pictures 3 and 4), while the lowest effect aqueous velvetleaf extract had on lettuce radicle length which was reduced by 37.4% (Pictures 1 and 2). The length of red beet radicle was reduced by 49.4% (Pictures 5 and 6). Inhibitory effect of velvetleaf was significant only on the length of carrot and red beet shoot while velvetleaf extract didn t inhibit lettuce shoot length when compared with untreated control. Results obtained in lettuce showed that velvetleaf had inhibitory effect only on the length of lettuce radicule. Inhibitory effect of velvetleaf on carrot and red beet shoot length (88.1% and 66.4%, respectively) was similar to effect on radicule length (83.8% and 49.4%, respectively). As shown, carrot shoot length was again the most inhibited. 128

133 Allelopathic effect of Abutilon theophrasti Med. on lettuce, carrot and red beet Fig. 1. Untreated lettuce (Photo: Šćepanović) Fig. 2. Lettuce on aqueous velvetleaf extract (Photo: Šćepanović) Fig. 3. Untreated carrot (Photo: Šćepanović) Fig. 4. Inhibited carrot on aqueous velvetleaf extract (Photo: Šćepanović) Fig. 5. Untreated red beet (Photo: Šćepanović) Fig. 6. Inhibited red beet on aqueous velvetleaf extract (Photo: Šćepanović) 129

134 Galzina et al. Lettuce was frequently test plant in previous studies on allelopathy. Quasem and Foy (2001) noted many references about different weed species allelopathic effect on crop plants. Many other weeds (Aristolochia clematitis, Cyperus esculentus, Galium aparine, Lolium multiflorum, L. perenne, Xanthium strumarium etc.) showed allelopathic effects on lettuce while allelopathic effects of different weeds (Amaranthus retroflexus, A. palmeri, Lepidium draba etc.) were less investigated in carrot. In addition to inhibitory effects, plants can act simulative. Golubić (2007) showed inhibitory effect of Echineacea spp. on lettuce germination and consequently the length of radicle and shoot. In contrast, Echinacea spp. stimulated all measured parameters in red beet. Results obtained agree with research of Novak (2007) and Šćepanović et al. (2007). Those authors also demonstrated a strong inhibitory effect of velvetleaf on some arable test plants. Other authors confirmed allelopathic effects of velvetleaf on some other vegetable crops. Gressel and Holm (1964) determined an inhibitory effect of velvetleaf seeds on early growth stages of tomato. Further, Retig et al. (1972) showed that cabbage grown with velvetleaf had larger roots, due to an increase in number and size of parenchyma cells. Houtz et al. in found that numerous glandular trichomes on velvetleaf stems and petioles exude liquid globules (in Sterling and Putnam, 1987). Because the exudate is water soluble, rain may enhance its movement into the soil where they can act as allelochemicals. Conclusions Aqueous velvetleaf extract had a significant effect on early development of lettuce, carrot and red beet. Velvetleaf showed the strongest inhibitory effect on carrot inhibiting carrot seed germination by 41.2%, length of radicle by 83.8% and length of shoot by 88.1%. In contrast, inhibition of the lettuce germination was the lowest and only radicle length was inhibited by velvetleaf extract. In red beet velvetleaf showed stronger inhibitory effect on shoot length (66.4%) than radicule length (49.4%). Of all tested plants, carrot was the most susceptible plant to velvetleaf extract, than red beet, while inhibitory effect was the smallest in lettuce. References FLEGAR Z. and NOVAK N Europski mraĉnjak (Abutilon theophrasti Med.). Zavod za zaštitu bilja u poljoprivredi i šumarstvu Republike Hrvatske. Ministarstvo poljoprivrede, šumarstva i vodnoga gospodarstva Republike Hrvatske, Zagreb. GOLUBIĆ, M Alelopatski utjecaj teofrastovog mraĉnjaka, kamilice i rudbekije na klijavost cikle i salate. Diplomski rad, Zagreb 130

135 Allelopathic effect of Abutilon theophrasti Med. on lettuce, carrot and red beet KAZINCZI, G., BÉRES, I., HORVÁTH, J., TAKÁCS, A. P Sunflower (Helianthus annuus) as recipient species in allelopathic research. Herbologia 5 (2): 19 MITICH, L. W Intriguing world of weeds. Velvetleaf. Weed Technology, 5: NOVAK, N Alelopatski utjecaj europskog mraĉnjaka (Abutilon theophrasti Med.) na neke poljoprivredne kulture. Magistarski rad, Zagreb QUASEM, J. R., FOY C. L Weed Allelopathy, Its Ecological Impacts and Future Prospects: A Review. In: Allelopathy in Agrecosystems (ed. Kohli R. K., Singh H. P., Batish D. R.), Food Products Press, Inc., NY, USA. RETIG, B., HOLM, L. G., STRUCKMEYER B. E Effects of Weeds on the Anatomy of Roots of Cabbage and Tomato. Weed Science, 20 (1): SATTIN, M., ZANIN, G. and BERTI A Case history for weed competition/population ecology: velvetleaf (Abutilon theophrasti) in corn (Zea mays). Weed Technol. 6: SCHLOSSER J. C. and FARKAŠ-VUKOTINOVIĆ L. (1869.) Flora Croatica, Zagrabiae STERLING T. M. and PUTNAM A. R., Possible role of glandular trichome exudates in interference by velvetleaf (Abutilon theophrasti). Weed Science 35: ŠĆEPANOVIĆ, M., NOVAK, N., BARIĆ, K., OSTOJIĆ, Z., GALZINA G., GORŠIĆ M Allelopathic effect of two weed species, Abutilon theophrasti Med. and Datura stramonium L. on germination and early growth of corn. Agronomski glasnik 6: ŠULEK B. (1879.). Jugoslavenski imenik bilja, Zagreb 131

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137 Herbologia Vol. 12, No. 1, 2011 COMPARISON BETWEEN ALLELOPATHIC AND COMPETITIVE RELATIONSHIPS BETWEEN SOME WEED SPECIES AND SMALL GRAINS BY GRAIN HARVEST INDEX ASPECT Olivera Nikolić 1, Sneţana Ţivanović Katić 2, Miodrag Jelić 3 1 Faculty of Ecological Agriculture, EDUCONS University, Sremska Kamenica, Serbia lolamisa@yahoo.com 2 Small Grains Research Center, Kragujevac, Serbia 3 Faculty of Agriculture, Zubin Potok, Serbia Abstract The aim of this investigation was to study allelopathic and competitive relationships between weeds and small grains by grain harvest index (GHI) of small grain in order to provide more information about these complex relationships. In the study were included small grains: wheat (Triticum aestivum), barley (Hordeum sativum), oat (Avena sativa L.), triticale (Triticosecale Witt.) and rye (Secale cereale) and some weed species: Agropyron repens, Cirsium arvense, Sonchus arvensis, and Sorghum halepense. Applied extracts of weed species mainly expressed suppressed effect on GHI, but stimulating actions were noticed, too. Positive influence, on GHI was registered at Agropyron repens and Sonchus arvensis variant in wheat and at Agropyron repens segments variant in oat. The most expressive grain harvest index decreasing was noticed in Sinapis arvensis variant, while oat showed the least sensitiveness towards weed presence by GHI aspect. The intensity of competitive relationships between weed species and wheat, considering grain harvest index, depended on sprouting quickness and percentage of studied weed species. Key words: allelopathy, competition, extract, weed, small grains, harvest index. Introduction Grain harvest index (GHI) presents ratio between economic (grain yield) and total biological yield (Donald and Hamblin, 1976). It is important indicator of small grains productivity. The higher value of GHI means better distribution of dry matter between vegetative and generative small grains organs. It means, in fact, better physiological efficiency of genotype in assimilates translocation from stems and leaves into spikes and grains (Djokić, 1988). After positive correlation between GHI and grain yield was found out, this parameter was recommended as criterion in small grains breeding for genotypes productivity improvement (Mayo, 1987; Sharma et al., 1987;

138 Nikolić et al. Richards, 2002). Some authors (Richards, 2002) stated that increasing grain yield was obtained owing to grain harvest index increasing, without increasing total biomass. Also, Moradi et al., (2008) set down further that oat and other small grains yield improvement might be achieved by combining high biological yield with high grain harvest index. Stressing factors cause decreasing of small grain yield that can be observed on the basis of its parameters. Knowing strong weed effect on grain yield it seems to be interesting studying the weed influence on some particular yield indicators and components like grain harvest index. This influence can be considered by weed and cultivated plants competitive aspect (Hashem et al., 1998). It is expected the weed presence lead to unfavorable conditions for plant growth, reflected to stem height and spike development. It can serve to provide better understanding and closer insight into very complex weed and cultivated plants competitive activity for nutrients, water, sunshine, etc (Gajic, 1966), but studying weeds and small grains relationships only by physical weed presence aspect is partial and incomplete. Many authors observed action of phytogenic substances of one species towards the same or other species, by physiological aspect. That chemical reaction between plants, based on metabolites, secreted out from root and other organs or products of plant residuals decomposition, is allelopathy (Graĉanin and Ilijanić, 1977: Singh et al. 2003). Weed allelopathic influences on small grains can be stimulating or inhibitory (Muminović, 1987: Sary et al. 2009). It has been still since the earliest plant growth phases by germination energy and total germination (Ognjanović et al. 1995). The most important allelopathic effect of weed is on small grains yield. Knowing the yield is complex trait, studying weed and small grains allelopathy by aspect of some indicators and components of productivity therefore could contribute to clearer explanation of that phenomenon. It can be especially usefull if investigation can be conducted in different conditions of cultivation, fertilization, sowing, crop protection etc. (Johnson et al., 2000). The allelopathy studying offers new possibilities for sustainable weed management. Qasem and Foy (2001) evaluated and discussed the importance, characteristics, positive and negative impacts and future role of weeds as an integral part of the natural and agroecosystems. Interference between plants in nature and the importance of differentiating between competition and allelopathy are interpreted. The use of allelopathy for controlling weeds could be either through directly utilizing natural allelopathic interactions, particulary of crop plants, or by using allelochemicals as natural herbicides (Singh et al., 2003). The aim of this investigation was to study allelopathic weed effect on grain harvest index, as an important yield indicator in small grains in order to 134

139 Comparison between allelopathic and competitive relationships between some... contribute to more complete investigation allelopathy between weed and small grains. Material and method The investigation was carried out in vegetative pots (volume 3,6 dm3) in glasshouse of Small grains Research Center, Kragujevac during 1999/ /02 in two part and in three replications (30 pots total). The next genotypes were included in the trial wheat cv. Takovĉanka, barley cv. Jagodinac, oat cv. Vranac, triticale cv. KG-20 and rye line L-307/4. The sowing was conducted during December, in density 25 seeds per pot. The influences of weed species, following Agropyron repens, Sonchus arvensis, Cirsium arvense and Sorghum halepense were explored. In the first part of trial, seed of investigated weeds were sowed into 15 sowed pots by 15 seeds per pot.in the second part of trial, 15 sowed pot was watered by each one glass (20 ml) of made extracts in accordance with trial variants, only once. The extracts were made by grinding dried whole weed plant (with root, in green phase). There upon, each 100 g of grinded mass was diluted by 4 l water. Such made extracts were left for two days. Besides these, the influence segments of A. repens was studied by putting 10 buds of that weed in each pot. The each part of trial included control variant without weed, too, watered by clear water and weeding by each 7-10 days. During winter period pots were located in glasshouse, but in greenhouse in spring and summer one. In the middle of February the number of small grains plants was reduced down to 12 plants per pot and top dressed by 1.5 g NPK fertilizer per pot. The small grains plants were harvested in phase of wax maturity and dried. Afterwards, biomass (under ground part) and grain yield per pot were measured. The obtained results were elaborated by analyze of variance and showed by tables. Results and discussion The sprouting time of weed seed was vary and ranged from simultaneously with small grains (Sonchus arvensis) to sprouting for six weeks after small grains sprouting (Agropyron repens and Cirsium arvense). The sprouting percentage varied, too, from 0 to 86.7%. Three years average GHI values for small grains species, planted in presence of weed are represented in Table 1. According to these, all studied small grains species had almost the same GHI in control variant, except rye with statistically high significant differences. Actually, rye had statistically high significant lower GHI values in all variants related to control and, considering that, expressed the most 135

140 Nikolić et al. sensitiveness under weed plants presence. On average for all variants, rye had high significantly lower GHI (30.3) related to other small grains. The weed almost caused statistically high significant differences in small grains GHI values from 28.6% (rye, C. arvense var.) up to 51.1% (oat, A. repens var.). It was registered, but, some small grains have higher GHI values in some weed variant related to control. It was noticed in wheat (44.1%, C. arvense var.), barley (50.0%, A. repens var.) and oat (51.1%, A. repens var). Seavers et al (1999) and Peltzer et al (1998) found out the weed influence on yield and GHI depends on weed density as well as wheat, oat and barley density, too. So, they concluded oat is the best competitor with weed in dense crop. C. arvensis has sprouted very slightly and slowly, non influencing hence small grains plant growth and grain forming and such values of GHI confirm these results. Table 1. Grain harvest index for various small grains species, average 1999/ /02 Weed species (B) Small grains species (A) Wheat Barley Oat Triticale Rye (B) Control A. repens C. arvense S. halepense S. arvensis (A) LSD A B A x B A small grains species B weed species 8.7 A x B interaction A. repens is especially dangerous weed species in small grains crops, effecting really high grain yield losses. In this investigation, however, some cultivars obtained higher grain harvest index in A. repens variant (even for 20%) related to control. Many authors (Williams, 1971; Bhagirath et al., 2006) reported the weed effect on grain yield is influenced by time and percentage of its sprouting. So, A. repens sprouted in tillering phase of small grains growth. Any more important influence could not be realized in that period. Muhammad (2000) reported its presence in wheat crop in the first 4-136

141 Comparison between allelopathic and competitive relationships between some... 6 weeks strongly effect decreasing of grain yield, weight of 1000 kernels and grain harvest index. Three years average GHI values for small grains species treated with weed extracts are represented in Table 2. Analyzing average GHI values (Tab. 2) it can be observed its varying from 28.2% in rye (S. halepense var.) to 45.8% in barley (control var.). The highest average values of GHI in all small grains species are recorded in control variant. Analyzing GHI values in investigation years it was observed its varying from 26% in rye (1999/00, C. arvense var.) to 47% in barley (2000/01, control). There were extra low values of this parameter even 18% in rye in some trial replications. Almost all extracts of studied weed species caused GHI reduction. Table 2. Grain harvest index for various small grains species, average 1999/ /02 Weed Small grains species (A) species (B) Wheat Barley Oat Triticale Rye (B) Control Segments A. repens Extract A. repens Extract C. arvense Extract S. halepense Extract S. arvensis (A) LSD A B A x B A small grains species B weed species A x B interaction There were however the examples of stimulate influences of some weed extracts on grain harvest index in wheat, 2001/02 in A. repens and S. arvensis var. and in oat in 1999/00 in variant with A. repens segments. The A. repens extract influence on oat GHI then ranged from neutral to negative. Kojić (1961) reported A. repens growing together with oat has not expressed negative influence on oat grain yield, even some improvement in oat grain yield was registered. That weed did not cause unfavorable changing many other traits, too. Chad et al. (2000) concluded adequate soil moisture can accelerate weed residue decomposition and, so, decrease allelopathy effects, in the field 137

142 Nikolić et al. conditions. Tepe et al. (2004) noticed more decreasing GHI values in conditions of physical weed presence, varying of 6.0% to 13.6%. On average for all variants, rye had high significantly lower GHI (30.3) related to other small grains, just like in the first part of trial. Differences between wheat, barley, oat and triticale were not statistically significant. On average for all small grains species, control variant had statistically high significant higher GHI (41.6%) related to all weed extracts variants. There were not statistically significant differences between all weed variants. Analyzing interaction between small grains species and weed extract variant, only suppressed weed extracts effects on GHI wheat, barley, oat, triticale and rye can be noticed. Except in rye and triticale, GHI decreases were significant in rest small grains in almost all variants. Chad et al. (2000), exploring influence of S. halepense residuals in soil expressed different (positive or negative) effect on GHI of various wheat cultivars. They emphasized the influence of quickness of weed residuals decomposition on value of this parameter. So, regular soil cultivating, rapid residual plaughing in and due-time wheat sowing instigate residual decomposition and hence make conditions for eliminating of allelopathy between S. halepense and wheat as well as other small grains. Hammouda et al. (1995) reported many factors affect intensity and direction of sorghum allelopathy. In fact, allelopathy is associated with concentration and effect of allelochemicals. The level of phenolics in residue, furthermore, depends on environmental conditions, plant part and development stage. They pointed out prompt tillage, after harvest, could alleviate allelopathy in field conditions. The highest GHI reduction was noticed in variant with A. repens segment, in wheat and in C. arvense variant in barley and oat. Kojić (1961) found out C. arvense extract strongly provoke decreasing of germination and keeping back of wheat root, leading to less values of grain yield and many its components and indicators. Conclusion Competition and allelopathy between weeds and small grains species can be investigated by aspect of grain harvest index as important genotype productivity indicator. Presence of weed and applied extracts of weed species mainly expressed suppressed effect on GHI. Presence of Sinapis arvensis plants caused the highest decreasing of this yield indicator in investigated cultivars while the highest negative influence were on extract of C. arvense and S. halepense. But in separate year stimulating actions were noticed, too. Positive influence, by GHI aspect was registered in A. repens and S. arvensis variant in wheat and in A. repens segments variant in oat. A. repens var. can be set aside in this regard among the results about competition. 138

143 Comparison between allelopathic and competitive relationships between some... Rye, among small grains, showed the highest sensitiveness towards presence of weed plants and weed extracts. Oat was the most resistant towards weed presence and wheat towards weed extracts, according to grain harvest index values. These results confirm, too, that yield is very complex trait and its studying and complete understanding need multidisciplinary investigations, by many aspects. References BEN HAMMOUDA, M., KREMER, R.J., MINOR, H. C.(1995): Phytotoxicity of extracts from sorghum plant components on wheat seedlings. Crop Sci., 35, BHAGIRATH, S.C., GILL, G., PRESTON, C. (2006): Factors affecting seed germination of annual sowthistle (Sonchus oleraceus) in southern Australia. Weed Science, 54, CHAD, M.R., JAMES, R., PAULSEN, S., PAULSEN, G.M. (2000): Alelopathy of Sorghum on wheat underseveral tillage systems. Agron.J., 92, DONALD, C. M. and HAMBLIN, J. (1976): The biological yield and harvest index of cereal as agronomic and plant breeding criteria. Adv. Agron., 28, DJOKIĆ, D.(1988): Pokazatelji akumulacije i iskorišćavanja azota u biljci kao agronomski i selekcioni kriterijum produktivnosti. Agrohemija, 1, GAJIĆ, D. 1966: Interspecifiĉni alelopatski odnosi izmeċu vrsta zastupljenih u karakteristiĉnoj kombinaciji fitocenološkog sistema korovske zajednice pšenice. Zbornik radova Instituta za biološka istraživanja, knjiga X, 10: GRAĈANIN, M. and ILIJANOVIĆ, LJ. (1977): Uvod u ekologiju bilja. Školska knjiga. Zagreb, HASHEM, A., RADOŠEVIĆ, S.R., ROUSH, M.L. 1998: Effect of proximity factors on competition between winter wheat (T. aestivum) and Italian ryegrass (Lolium multiflorum). Weed Science. 46: JOHNSON, G., BLOOGETT, S., CARLSON, G., GREY, W., LENSSEN, A., MATHRE, D., MAYO, O.(1987): The Theory of Plant Breeding. Oxford Science Publications. University of Adelaide, GB KOJIĆ, M.(1961): Korovi: osobine-vrste-suzbijanje.zadruţna knjiga, Beograd MORADI, M., REZAI, A.M., ARZANI, A. (2008): Genetic improvement in grain yield and related traits in oat cultivars released in Canada during J. Sci. and Technol. Agric. and Natur. Resour., 11, 112. MUHAMMAD, S.C. 2000: Seeding wheat in a standing cotton crop. Item from Pakistan. AWN, vol. 41: 154. MUMINOVIĆ, Š. (1987): Alelopatski uticaj ekstrakata nekih vrsta korova na klijavost semena pšenice. Fragmenta herbologica Jugoslavica. 16, QASEM, J.R., FOY, C.L.(2001): Weed allelopathy, its ecological impacts and future prospects. Journal of crop production, 4, OGNJANOVIĆ, R., STOJANOVIĆ, J., LOMOVIĆ, S., PANTIĆ, R., MIHAJLIJA, D. (1995) Alelopatski uticaj semena nekih korovskih vrsta na klijanje pšenice. Selekcija i semenarstvo. II, PELTZER, S., VERBEEK, B. (1998): The effect of increasing wheat density on ryegrass management. Agriculture Western Australia. NSW Agriculture and CRC for weed management: 234. SEAVERS, G.P., WRIGHT, K.J. (1999): Crop canopy development and structure influence weed suppression. Weed Research, 39. 4:

144 Nikolić et al. RICHARDS, R.A. (2002): Selectable traits to increase crop photosynthesis and yield of grain crops. Journal of Experimental Botany, 47, SARY, G.A., EL NAGGAR, H.M., KABESH, M.O., EL ARAMANY, M.F., BAKHAUM GEHAN, Sh.H.(2009): Effect of bio organic fertilization and some weed control treatments on yield and yield components of wheat. World Journal of Agricultural Sciences, 5, SHARMA,S.K., Singh, V.P., Singh, R.K. (1987): Harvest index as a criterion for selection in wheat. Indian J. Genet. Plant Breed., 47, SINGH, H.P., BATISH, D.R., KOHLI, R.K (2003).: Allelopathic interactions and allelochemicals: new possibilities for sustainable weed management. Critical Reviews in Plant Sciences, 22, TEPE, I., ERMAN, M., YAZLIC, A., LEVENT, R., IPEN, K.(2004): Comparison of some winter lentil cultivars in weed crops competition. Crop Protection, 24, WILLIAMS, E. D. (1971): Germination of seeds and emetgence of seedlings of Agropyron repens (L.) beauv. Weed Research, 11,

145 Herbologia Vol. 12, No. 1, 2011 RELATION OF YIELD AND GRAIN HARVEST INDEX IN WHEAT BY WEED INFLUENCE ASPECT Olivera Nikolić 1, Sneţana Ţivanović Katić 2, Miodrag Jelić 3, Ivica Đalović 4 1 Faculty of Ecological Agriculture, EDUCONS University, Sremska Kamenica, Serbia lolamisa@yahoo.com 2 Small Grains Research Center, Kragujevac, Serbia 3 Faculty of Agriculture, Lesak, Serbia 4 Institute of Field and Vegetable Crops, Novi Sad, Serbia Abstract The aim of this investigation was to study the relation of yield and grain harvest index in wheat by weed influence aspect in order to provide more data on their relationship. Three wheat cultivars were involved in this investigation, namely Takovĉanka, Gruţa and Pesma. The following weed species were tested for their influence on wheat productive traits: Cirsium arvense, Avena fatua, Consolida regalis, Sinapis arvensis, Sonchus arvensis, Daucus carota, Setaria glauca and and Datura stramonium. The 15 seeds per weed species were sown simultaneously with wheat (25 seeds). The grain yield decrease was statistically significant for Avena fatua and Cirsium arvense var., and highly significant for others, compared to weed free control. The most expressive grain harvest index decreasing was noticed in Sinapis arvensis var. Gruţa expressed the highest tolerance towards weed influence, according to grain yield, although Pesma was the least sensitive towards weed, considering GHI values. Key words: grain harvest index, weed, wheat, yield. Introduction The grain harvest index is defined as ratio between economic (grain yield) and biomass yield (Donald, 1962). Its higher value represents just better dry matter distribution between vegetative and generative plant parts. This indicator was named still coefficient of efficiency or translocation (Niĉiporoviĉ, 1966). The grain harvest index is a very important indicator of genotypes yielding potential, but many other traits, too. Numerous explorations have found out positive correlation between GHI and grain yield (Fisher and Kertesz, 1976; Bhatt, 1976: Mayo, 1987). Some authors (Richards, 2002) stated that increasing grain yield was obtained owing to grain harvest index increasing, without increasing total biomass. Also, Moradi et al., (2008) set down further that oat and other small grains yield

146 Nikolić et al. improvement might be achieved by combining high biological yield with high grain harvest index. There are investigations, too, that register its instability of the weather conditions, plant number and many other factors which reduced its association with yield (Nikolić, 2009). So, studying of yield and GHI relation, by various aspects, is necessary and useful for understanding its complex dependence. Weeds, as regular cohabitants of cultivated crops, are known to cause damage to crops and great yield losses. Not all weed species are equally dangerous for cultivated plants. Therefore, it is very important to study the influence of individual weeds on cultivated plants in order to be able to plan potential grain yield decreases. Many authors have reported that weed effect on grain yield is influenced by quickness and percentage of its sprouting (Ţivanović Katić et al., 2004; Marinov-Serafimov et al., 2007; Bhagirath et al., 2006) and that, furthermore, germination and emergence depend on the sowing depth (Tanveer et al., 2010). In struggling against weeds it is important to determine the economic tolerance level weed individual numbers in crop which can be tolerated without significant negative effect on yield (Hassan and Yousafzai, 2006, Nakova, 2008). In accordance with it, studying the weed influence on some particular yield indicators and components like grain harvest index it seems to be interesting. This influence can be considered by weed and cultivated plants competitive aspect (Hashem et al., 1998). The aim of this investigation was to study the relation of yield and GHI, by weed aspect, in order to contribute to better understanding its complex dependence. Material and method The investigation was performed in vegetative pots, with three replications in the greenhouse of the Small Grains Research Center in Kragujevac, over the period of 1999/00 and 2000/01. Three wheat cultivars were sown in December (25 seeds per pot), namely Takovĉanka, Gruţa and Pesma and weed species were sown simultaneously (15 seeds per pot). The weeds included in this trial were Cirsium arvense (L.) Scop., Avena fatua L., Consolida regalis S. F. Gray, Sinapis arvensis L., Sonchus arvensis L., Daucus carota L., Setaria glauca (L.) P.B. and Datura stramonium L. Besides these variants, two other variants were tested in the experiment the self-sprouted weed control and weed-free control, weeded at 7-10 days intervals, as sprouting/germination of sown weeds has been observed to occur at such intervals. During winter period pots were placed in the greenhouse and during spring and summer in the vegetative house. 142

147 Relation of yield and grain harvest index in wheat by weed influence aspect Wheat plants number was reduced down to 12 per pot in the mid - February. At the same time 1.5 g NPK was added to each pot. Consolida regalis seeds failed to sprout. As a result, five plants were replanted to each pot from the field, considering the species, frequent occurrence in wheat crops as well as its effect on grain yield of wheat. Wheat plants were harvested in the phase of wax maturity and dried. Afterwards, the biomass and grain yield per pot were measured. The grain harvest index was counted as ratio between grain yield per pot and total above ground biomass yield per pot. It was expressed in percentage. The obtained results were processed by the analysis of variance and shown in the tables. Results and discussion Comparing grain yield of the investigated wheat cultivars in all variants, the highest one was found in the weed free control variant (Gruţa, g pot -1, Table 1). Only the Pesma cv. achieved a higher yield (11.33 g pot -1 ) in weed presence (Cirsium arvense variant) than in weed - free control (8.69 g pot -1 ), but that difference was not statistically significant. Table 1. Grain yield of wheat cultivars (g/pot) in various weed variants, two year average Wheat cultivars (A) Weed species (B) Takovĉanka Gruţa Pesma (B) Weed -free control Control Avena fatua L Cirsium arvense (L) Scop Consolida regalis L Daucus carota L Setaria glauca (L) P.B Sinapis arvensis L Sonchus arvensis L (A) LSD A B A x B A wheat cultivar B weed species A x B interaction Averagely, the best grain yield was obtained by cv. Gruţa (10.11 g pot -1 ), although differences between genotypes were not statistically significant. The grain yield decrease was statistically significant for Avena fatua and Cirsium arvense variants, but highly significant for others, compared to the weed free control. Popović and Maksimović (1978), Perić, Đ. (1990), Nakova and Nikolov (2005) emphasized that wild oat is one of the 143

148 Nikolić et al. riskiest weeds in small grain crop due to its quick growth over the first weeks after sprouting. Wild oat is thus a very strong competitor with small grains. In this investigation, but, Avena fatua seeds sprouted six weeks after sowing, when the wheat plant were in the 2 4 leaves phase. Hence its influence was not so important from the grain yield aspect. Taking into consideration the fact that all weed species do not carry the same risk for cultivated plants, economic tolerance levels of weeds for cultivated plants need to be determined. This investigation showed, for example, that five Consolida regalis plants (replanted from the field) had equally unfavorable influence on wheat grain yield as ten Avena fatua plants (supposing they sprouted simultaneously). The highest percentage of sprouted seeds per pot, out of total seeds sown, was found in Sinapis arvensis and Daucus carota var. (13 sprouted seeds or 86,7%), but the lowest in Sonchus arvensis var. (13,3%). The period of sprouting among weed species varied, too. Many authors have reported that weed effect on grain yield is influenced by quickness and percentage of its sprouting (Ţivanović Katić et al., 2004; Marinov-Serafimov et al., 2007; Bhagirath et al., 2006). Sinapis arvensis seeds sprouted at the same time as wheat seeds, at a very high percentage and affected the highest decrease of grain yield in this investigation. Daucus carota seeds were found to sprout 2 3 weeks after wheat and affected grain yield more negatively than Sonchus arvensis species, which appeared at a later stage of wheat developing and growth. Table 2. Grain harvest index (%) in various weed variants, two year average Wheat cultivars (A) Weed species (B) Takovĉanka Gruţa Pesma (B) Weed -free control Control Avena fatua L Cirsium arvense (L) Scop Consolida regalis L Daucus carota L Setaria glauca (L) P.B Sinapis arvensis L Sonchus arvensis L (A) LSD A B A x B A wheat cultivar B weed species A x B interaction That difference did not occur with GHI values (Table 2). The influence of Avena fatua L. on GHI of wheat was especially interesting. Actually, wheat GHI value was the highest in Avena fatua L. variant (47), 144

149 Relation of yield and grain harvest index in wheat by weed influence aspect statistically significant in relation to the weed free control and Consolida regalis L. variant and highly significant in relation to the control and Setaria glauca variant. The reason for this unexpected influence could be the later sprouting of weed, even in the tillering phase of wheat. Any more important influence could not be realized in that period. Muhammad (2000) reported its presence in wheat crop in the first 4-6 weeks strongly effect decreasing of grain yield, weight of 1000 kernels and grain harvest index. In wild oat free wheat crop, in that period, such influences disappeared. The most sensitive genotypes under weed plant presence, considering grain harvest index values, were Takovĉanka and Gruţa, while Pesma obtained a relatively high GHI value, statistically highly significant, mainly, as in most variants so on an average. The highest grain harvest index decrease was registered in the variants Sinapis arvensis, as it was recorded with the grain yield, while the highest GHI value was obtained in Avena fatua L. variant. The impact of weeds on grain yield was consistent with their effect on the GHI for the control and Sonchus arvensis L. variant (Takovĉanka cv.) and Avena fatua L. and Setaria glauca variants (Pesma cv.). For the mentioned variants, these cultivars obtained the highest values of grain yield, as well as for the GHI. The lowest values of both traits were registered for the variants: control (Pesma), Avena fatua L. (Takovĉanka), Cirsium arvense (Gruţa), Consolida regalis (Gruţa), Daucus carota (Takovĉanka), Setaria glauca (Takovĉanka) and Sonchus arvensis L (Pesma), indicating the identical influence of weeds on wheat grain yield and GHI. Conclusions Weeds represent one of the risk factors for cultivated plants, including wheat. Their presence causes grain yield decrease and, mainly, grain harvest index decreasing. Sinapis arvensis expressed the strongest influence, in the sense of decreasing the values of these parameters. The tested cultivars obtained the best results of grain yield in the weed free control variant, while the highest GHI value was registered for Avena fatua one. Cv. Gruţa was the most resistant towards the weeds, having the best yield, but Pesma cv. had the highest GHI value. The depressing effect of weeds depends on the quickness and percentage of its sprouting. The investigated weed species act on the grain yield and harvest index, mainly, in the same direction, increasing or decreasing them, but there were cases where the impact was not identical. These results once again confirm that the grain yield is a complex trait, resulting from various 145

150 Nikolić et al. reactions and the relationships of various parameters. As possible a better understanding of this important economic trait requires to studying it with the most diverse aspects of the context of different factors. References BHAGIRATH, S.C., GILL, G., PRESTON, C. (2006): Factors affecting seed germination of annual sowthistle (Sonchus oleraceus) in southern Australia. Weed Science, 54, BHATT, G.M. (1976): Variation of harvest index in several wheat crosses. Euphytica, 25, DONALD, C.M. (1962): In search of yield. Austr. J. Agric. Res., 28, FISCHER, R.A., KERTESZ, Z. (1976): Harvest index in spaced populations and grain weight in microplots as indicators of yielding ability in spring wheat. Crop Sci., 16, HASSAN, G., H.YOUSAFZAI, (2006): Effect of wild oat (A.fatua) density on wheat yield and its components under various nitrogen regimes. Herbologia, 7, 2, HASHEM, A., RADOSHEVICH, S.R., ROUSH, M.L. (1998): Effect of proximity factors on competition between winter wheat (T. aestivum) and Italian ryegrass (Lolium multiflorum). Weed Science. 46, MARINOV-SERAFIMOV, P., DIMITROVA, T., GOLUBINOVA, I., ILIEVA, A. (2007): Study of suitability of some solutions in allelopathic researchers. Herbologia, 8, 1, MAYO, O. (1987): The Theory of Plant Breeding. Oxford Science Publications. University of Adelaide, GB MORADI, M., REZAI, A.M., ARZANI, A. (2008): Genetic improvement in grain yield and related traits in oat cultivars released in Canada during J. Sci. and Technol. Agric. and Natur. Resour., 11, 112. MUHAMMAD, S.C. (2000): Seeding wheat in a standing cotton crop. Item from Pakistan. AWN, 41, 154. NAKOVA, R. (2008): Cirsium arvense (L.) Scop. competition with winter wheat. Herbologia, 9, 2, 1 8. NAKOVA, R., NIKOLOV, P. (2005): Preliminary studies on competition between Avena fatua L. and Galium aparine L. Herbologia, 6, 3, NIĈIPOROVIĈ, A.А. (1966): Zadaĉi rabot po izuĉeniju fotosintetiĉeskoj dejatelnosti rastenij kak faktora produktivnosti. Fotosintezirujušĉie sistemi visokoj produktivnosti. Nauka, Moskva. NIKOLIĆ, O. (2009): Genetiĉka divergentnost genotipova pšenice za parameter efikasnosti ishrane azotom. Doktorska disertacija. Poljoprivredni fakultet, Beograd Zemun, PERIĆ, Đ. (1990): Uticaj naĉina obrade zemljišta na prinos pšenice i pojavu korova. Savremena poljoprivreda, 38, 5 6, POPOVIĆ, A., MAKSIMOVIĆ, D. (1978): Yield potential of certain European spring oat varieties. Oat Newsletter, 29, RICHARDS, R.A. (2002): Selectable traits to increase crop photosynthesis and yield of grain crops. Journal of Experimental Botany, 47, TANVEER, A., MUHAMMAD A.N., MUHAMMAD M.J., AHSAN, A., RANA N.A., ASGHAR A. (2010): Comparison of emergence of wheat, barley, oat and their associated weeds at different burial depths. Herbologia, 11, 1,

151 Relation of yield and grain harvest index in wheat by weed influence aspect ŢIVANOVIĆ KATIĆ, S., NIKOLIĆ, O., STOJANOVIĆ, J., JELIĆ, M. (2004): Competitive relationships between some weed species and wheat. Acta herbologica, 13, 1,

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153 Herbologia Vol. 12, No. 1, 2011 DORMANCY AND WEED SEED GERMINATION Mirha Đikić 1, Drena Gadţo 1, Teofil Gavrić 1, Vildana Šapčanin 2, Adnana Podrug 1 1 Faculty of Agriculture and Food Sciences, Zmaja od Bosne 8, Sarajevo, m.djikic@ppf.unsa.ba 2 Professional School of Agriculture, Food Processing, Veterinary, and Service Industry in Sarajevo, Hamdije Kreševljakovića 55, Sarajevo Summary In recent years, many studies in weed science are focused on biology and ecology of weeds. Knowing of weed infestation of agricultural areas is directly dependent on knowing of the time and the dynamics of weed seed germination, as well as the factors which are affecting them. Application of the knowledge about the dynamics of seed banks in soil as well as predicting the time of weed emergence in the models for weed control would enable the reduction of the herbicide use without any influence on the crop yield and level of weed control, with the same or increased economic impact. This paper presents results of testing of seed germination and breaking dormancy of the following weeds: johnsongrass (Sorghum halepense), velvetleaf (Abutilon theophrasti), quackgrass (Agropyron repens) and thorn apple (Datura stramonium). Six different methods of breaking weed dormancy were applied. Method of heating to 80 centigrades showed the best result regarding the breaking dormancy of the investigated weeds. Keywords: dormancy, johnsongrass, quackgrass, thorn apple, velvetleaf, weed germination Introduction European Weed Research Society defines the weeds as plants that grow in places where they are not desirable and that they conflict with the man needs. Continuous presence of weeds on arable land initiates a constant fight against them. Problems appeared as a result of excessive use of pesticides in conventional production, particularly in developed countries. It has initiated the development of the concept of sustainable agriculture, and one of its key elements is to find alternative methods of weed control. In relation to crops, the weeds characterize specific features that distinguish them in special category of plants. These features are: adaptation, periodicity of germination, resistance to adverse conditions and great reproductivity (Šarić, 1991). The fact that some weeds can give even a

154 Đikić et al. million seeds per plant (e.g. pigweed), and can germinate after 50 years in soil, points up the need for more detailed understanding of this group of plants. Land contains constant supply of weed seeds. Its amount depends on natural conditions, weed species and applied cropping practices. According to Konstantinović et al. (2008) (cited Baker, 1989), the definition of seed bank is the amount of seeds which is found in soil, which is able to germinate and give new life of annual and perennial weeds. In recent years, in order to find acceptable methods of weed control, the investigation related to weed seed bank is intensified. Ambrosio et al. (2004) stated that understanding of seed bank is necessary in order to put forward a study of dynamics population and to establish the programs for weed control. According to Zhang et al. (1998), the prediction of possible solution should be based on the knowledge of the active seeds reserve in the soil up to the depth of 15 cm. The seeds reserve in the soil is under direct influences of the applied strategies of weed control. Mayor and Dessaint (1998) state that the soil seedbank density of germinated weed seeds (m 2 ) ranged from the smallest obtained in chemical weed control (2,765) to the largest obtained by mechanical suppression (43,274). Knowledge of factors influencing weed seed germination is important to predict infestation levels and to plan control strategies (Paolini et al., 1999). In weed control strategy, our main interest is whether weed seed germinate. However, there are weed seeds that germinate from time to time. Those are dormant seeds. Dyer (1995) states that factors such as light penetration, soil water content, soil fertility, and temperature are modified by soil tillage, planting, harvesting, and other production practices, resulting in enhanced or depressed weed seed germination. Dormancy is a phenomenon in which seeds of some plants do not germinate immediately after maturation, although all conditions for germination are provided. A large number of species of temperate zone sporulate and rash at the end of vegetation. If the seeds have no dormancy, under favourable conditions the seeds will germinate during hot and humid autumn. First frost will destroy the weed seedlings. Because of that, dormancy is a biological mechanism to adapt to seasonal changes, such as the need for cooling during the winter, or washing of inhibitors on the begining of the rainy season (Grbić, 2003). In some kind of plants, adaptive mechanism is reflected in the somatic seed polymorphism expressed through a different willingness to seed germinate. The genus Alopecurus in the same spike has a dormant seed, seed that germinates immediately after dissemination and viviparous seeds (which 150

155 Dormancy and weed seed germination germinate in spike). Genus Xanthium has two seeds in the fruit, one germinates the same year, second one germinates next year. Chenopodium album has two types of seeds that differ in colour: the lighter one which germinates immediately and darker one which is dormant (Grbić, 2003). Some species may evolve a second dormancy if they are exposed to higher or lower temperature than those required for intensive germination. Bares and Sardi (1999) reported that dormancy play an important role in germination of barnyardgrass (Echonochloa crus-galli) and yellow foxtail (Setaria glauca). The same authors state that in the last few decades, research in weed biology mostly focused to the mechanisms of dormancy. Results of this research provided essential information on the physiology and biochemistry of dormancy. In controlling the dormancy, environmental factors are of primary importance. Wyse (1992) states that if weed science explains the phenomena of the weed genetic population, seed dormancy and nature of allelopathic relationships, then it will fulfill a basic prerequisite to weed science and weed management to prove a vital factor of sustainable agriculture. The aim of our investigation was to study seed germination and breaking dormancy of following weeds: johnsonngrass (Sorghum halepense), velvetleaf (Abutilon theophrasti), quackgrass (Agropyron repens), and thorn apple (Datura stramonium). Johnsongrass and quackgrass belong to the most widespread weeds under our environmental conditions, while velvetleaf and thorn apple are two invasive species which have spread on arable land recently. Materials and methods Testing of germination and dormancy of weed seeds was done at the Seed Laboratory of the Faculty of Agriculture and Food Sciences in Sarajevo. The experiment included the seeds of johnsongrass harvested in 1999 and Other weed seeds were harvested in The seeds were kept in laboratory at room temperature. The following variants were included in the experiment: - chemical treatment - use of 0.2% KNO 3 - mechanical scarification of seeds - soaking seeds in water for 24 hours - cold stratification, i.e. pre-chilling of seeds to +4 0 C for 7 days, - cold stratification, i.e. pre-chilling of seeds to +4 0 C for 14 days, - method of heating (water heated to 80 0 C, then is removed from the oven, the weed seeds are sunk in water and left to cool down to room temperature) - standard seed germinating procedure, according to the Rulebook on 151

156 Đikić et al. germination (control) All tested variants were performed in four replications. The standard procedure for testing weed germination lasted for 15 days at 23 0 C in germinator. Petri dishes coated with filter paper were used for germination. In each Petri dish we placed 30 weed seeds. For the cold stratification methods (lasting 7 or 14 days) plastic bags were used. That method is named naked stratification. During the investigation we recorded the number of germinated weed seeds and seedling mass. The results were statistically analyzed using SPSS program (analysis of variance and t-test). Results and discussion The results of germination and breaking of weed seeds dormancy are presented in the following tables. Variant Table 1. Percent of germinated weed seeds Sorghu m halepense 1999 Sorghu m halepense 2008 Abutilon theoprasti Agropyron repens Datura stramonium Chemical treatment with 0.2% KNO 3 Mechanical scarification ** Soaking seeds in water 34.2 ** * for 24 hours Pre-chilling of seeds to +4 0 C for 7 days Pre-chilling of seeds to +4 0 C for 14 days Heating 29.2 ** 30.0 ** 62.5 ** ** Control Germination of weed seeds presented in the control variants shows a very low percent of germinated seeds in comparison to the seed number put in Petri dish (30 seeds). The heating method has proven to be the best for seed dormancy breaking. Except Agropyron repens, other species had a significant higher percent of germinated seeds compared to control, especially Abutilon theoprasti and Datura stramonium (62.5 and 56.7 respectively). Method of 24-hour soaking seeds in water also caused increasing germination in Sorghum halepense from 1999 and Abutilon theoprasti (34.2 and 17.5%, respectively). Mechanical scarification of seeds 152

157 Dormancy and weed seed germination was effective only for Datura stramonium. Only Agropyron repens seeds did not germinate much more depending to applied methods. Salimi and Termeh (2002) got similar results. Chemical scarification by sulfuric acid for 45 minutes and high temperature treatment of 50 and 90 0 C caused seed dormancy breaking in Echinochloa crus-galli and Sorghum halepense, respectively. Nurse and DiTommaso (2005) seeds of velvetleaf were soaked in boiling water in gauze for 10 seconds, then placed on filter paper moistened with distilled water in Petri dishes on a lab countertop at room temperature (22 0 C). Nearly all seeds germinated within 3 days. Ekpong (2009) in his paper got the similar result. When mature seeds of cleome (Cleome gynandra) were subjected to different treatments, including various levels of GA, KNO 3, leaching, pre-chilling, soaking and pre-heating at different temperatures, it was found that pre-heating at 40 C for a period of 1 5 days was the most effective method in breaking dormancy in mentioned plant. Egley (1990) investigated eight weed species which were heated for up to 7 days at 40, 50, 60, and 70 0 C in dry (2% moisture) and moist (19% moisture) sandy loam to determine temperature-time treatments lethal to weed seeds. Seeds in dry soil were very tolerant to 60 0 C or less for up to 7 days but most seeds were killed at 70 0 C after 7 days. In moist soil, a few (1 to 12%) seeds of common purslane, redroot pigweed, johnsongrass, and spurred anoda survived for up to 3 days at 70 0 C. Janaiah et al (2004) concluded that among various treatments tried for breaking seed dormancy of 18 rice cultivars, dry heat treatment (50 0 C, 7 days) was most effective bringing the germination to 90% or above in all varieties immediately after harvest. Seedling weed mass of investigated weeds were significantly higher in S. halepense (1999), A. theoprasti and D. stramonium with heating to 80 centigrades (0.27; 1.13 and 0.79, respectively). In the variant of mechanical scarification D. stramonium seeds, 24-hour soaking S. halepense (1999), prechilling for 7 days A. teophrasti seeds has also been significantly higher weight compared to control. Variant Chemical treatment use of 0.2% KNO 3 Table 2. Mass of weed seedlings, g Sorghu m halepense 1999 Sorghum halepense 2008 Abutilon theoprasti Agropyron repens Datura stramonium

158 Đikić et al. Mechanical scarification ** Soaking seeds in water 0.32 ** for 24 hours Pre-chilling of seeds ** at +4 0 C for 7 days Pre-chilling of seeds at +4 0 C for 14 days Heating 0.27 ** ** ** Control LSD 5% 1% Conclusions Dormancy is a very important weed seed property. In recent years many authors have tryed to explain it more detailed. In our investigation we found some results that confirm with others, but some did not. Heating method was the most successful in comparation to others. If we compare S. halepense seeds from 1999 and 2008 we can see that seeds had viability after ten years of storage, and showed better results in germination than seeds from Literature AMBROSIO, L.A., L. IGLESIAS, C. MARIN, J. P. MONTE (2004): Evaluation of sampling methods and assessment of the sample size to estimate the weed seedbank in soil, taking into account spatial variability. Weed Research 44, BARES, I., K. SARDI (1999): Effect of stratification, light and nitrate on the germination of Echinochloa crus-galli (L) P.B. and Setaria glauca (L). Proc. 11th EWRS Sym., Basel, Switzerland. 10. DYER, W.E. (1995): Exploiting weed seed dormancy and germination requirements through agronomic practices. Weed Science, 43, EGLEY, G. H. (1990): High-Temperature Effects on Germination and Survival of Weed Seeds in Soil. Weed Science, No. 38, EKPONG, B. (2009): Effects of seed maturity, seed storage and pre-germination treatments on seed germination of cleome (Cleome gynandra L.), Scientia Horticulturae, Vol. 119, No. 3, GRBIĆ, M. (2003): Dormantnost i klijanje sjemena mehanizmi, klasifikacije i postupci. Glasnik Šumarskog fakulteta, Beograd, br. 87, str JANAIAH, K., K. KANT, MALAVIKA DADLANI (2004): Chemical regulation of dormancy behaviour in rice cultivars. Book of Abstracts, 3rd International Symposium on Plant Dormancy. Wageningen, The Netherlands KONSTANTINOVIĆ, B., MAJA MASELDŢIJA, B. KONSTANTINOVIĆ, NATAŠA MANDIĆ (2008): Ispitivanje banke semena korova pod usevom soje. Acta Herbologica, Vol 17, No.1,

159 Dormancy and weed seed germination MAYOR, P.J., F. DESSAINT (1998): Influence of weed management strategies on soil seedbank diversity. Weed Research, 38, NURSE R.E., A. DITOMMASO (2005): Corn competition alters the germinability of velvetleaf (Abutilon theophrasti ) seeds, Weed Science, 53: PAOLINI, R., C. ROCCHI, P. BARBERI (1999): Germination of Sinapis arvensis L. as influenced by seed traits, pre-chilling and light. Proc. of 11th EWRS Sym., Basel, Switzerland. 14. SALIMI, H., F. TERMEH (2002): A study on seed dormancy and germination in ten species of grass weeds. Proc. of 12th EWRS Symp. Wageningen, Netherlands. ŠARIĆ, T. (1991): Korovi i njihovo uništavanje herbicidima. VII izdanje. Zadrugar, Sarajevo. WISE, D. L. (1992): Future of weed science research. Weed technology, Vol. 6: ZHANG, J., S. A. HAMILL, O. I. GARDINER, E. S. WEAVER (1998): Dependence of weed flora on the active soil seedbank. Weed Research. 38,

160 Herbologia Vol. 12, No. 1, 2011

161 Herbologia Vol. 12, No. 1, 2011 MAPPING OF INVASIVE SPECIES AMBROSIA ARTEMISIIFOLIA L. BY AMBROSIA SPOT MARKER SOFTWARE Branko Konstantinović 1, Maja Meseldţija 1, Bojan Konstantinović 2 1 Faculty of Agriculture, Trg Dositeja Obradovica 8, Novi Sad 2 Agrimatco Group Dipkom, Narodnog fronta 73,Novi Sad brankok@polj.uns.ac.rs Abstract Weedy-ruderal species Ambrosia artemisiifolia L. (fam. Asteraceae) is in the phase of fast and intensive spread on the territory of the Republic of Serbia, to which it has been introduced from the neighboring European countries. It belongs to adventive floristic element and it is believed that it was introduced into Europe in 1800 from North and Middle America together with contaminated clover seed (Priszter, 1960). On the territory of Vojvodina, the northern part of the Republic of Serbia it was found on the banks of the river Danube, near Petrovaradin, Sremski Karlovci and Novi Sad, as well as near Bogojevo, Odţaci, Baĉ and Baĉka Palanka. It has been spreading northwards near Kula, Begeĉ and Futog in the region of Baĉka, as well as in central and south Banat. As problem of adventive and invasive weeds is not of local character and that spread of such species is determined quite late, when they already become problematic, terrain monitoring, as well as exchange of information between stations that monitor these processes are important. Studies performed in the period on over 400 ha of non/agricultural and ruderal areas on the territory of the city of Novi Sad, A. artemisiifolia was determined on over 200 locations. Studies were carried over on uncultivated and green areas, and for mapping and distribution of the species, modified method of Brauen-Blanquet (1951) was used. For data processing the specially designed software program Ambrosia Spot Marker (Konstantinovic et al, 2008) was used. During growing season, monitoring of this species was performed because it s spatial spread, as well as the occurrence of retro vegetation after mowing or chemical control. During the period of studies, Ragweed is found in over 200 locations in 21 urban areas of Novi Sad. Mapping, determination of abundance and coverage of this invasive species during vegetation period from April to October in the three-year study, showed that the highest number of A. artemisiifolia was 50 plants per m 2. For each city area maps were made in the program Ambrosia Spot Marker. Key words: mapping, Ambrosia artemisiifolia, Novi Sad, Ambrosia Spot Marker softwer

162 Konstantinović et al. Introduction Each year, great number of invasive plant weed is introduced into new areas. However, only limited number of them is able to develop population while inhabiting new habitats (Jauzein, 1998). The major characteristic of invasive plant is their high reproductive capability that implies production of greater seed quantity per plant that easily and fast spread into greater areas and have small demands concerning conditions for emergence and shooting. The additional characteristic of invasive species is their capability of adaptation to different environmental conditions, as well as ability of exploitation that leads to disturbance of existing environmental conditions (Ravinder et al., 2009). Based on previous experience it was established that adventive plant species that inhabit arable areas may become very problematic weeds in conditions of unchanging technology of weed control (Maillet and Lopez-Garcia, 2000). This is possible for biological-ecological characteristics of certain families or phylogenetic relatedness of families can speed up their success as invasive weeds. This is the case with many adventive species belonging to the family Asteraceae that became very dangerous and aggressive weeds in Serbia, such as Ambrosia artemisiifolia L., Artemisia vulgaris L., Asclepias syriaca L., Iva xanthifolia Nutt., Xanthium strumarium L. (Konstantinovic, 2008). With development of transport and trade in last thousand years humans accidentally or purposely introduced different plant species in new ecosystems (Mack et al., 2000). Spreading of species that are not native for certain area, i.e. habitat became global problem that rose also in Serbia. Concerning the total diversity of segetal florae that consists of 1009 taxons, i.e. 28% of the total vascular florae of Serbia (Vrbnicanin and Janic, 2003), to the group of invasive adventive species belong 97 ones, i.e. 9.6%. Within these species, the most distributed are representatives of families Asteraceae and Poaceae. According to the study of Igic et al. (2005) at the territory of the city of Novi Sad 44 allergenic weed species were determined as the most dangerous for human organism. Ambrosia artemisiifolia L. was the wildest distributed and was found in suburbs of the city, as well as on and the neglected places in the city, near banks of the Danube, DTD Channel, i.e. it was established that ragweed populations surround the city. The first data on the existence of ragweed in our country in beans, potatoes, corn and wheat crops published Maly (1949). Slavnic (1953) recorded this species for the first time in Serbia near Sremski Karlovci, Petrovaradin and Novi Sad. From these focuses, ragweed spread all over Vojvodina, and for the last 60 years invaded all territory of Serbia (Konstantinovic, 2008). 158

163 Mapping of invasive species Ambrosia artemisifolia L. by ambrosia spot marker.. Materials and methods In the period on the territory of the municipality Novi Sad, terrain studies of A. artemisiifolia L. distribution, as well as mapping were performed on regulated and disordered green areas and on arable areas. For mapping of ragweed distribution, partially modified method of Braun- Blanquet (1951) was used, and data processing was performed by for the purpose specially designed program Ambrosia Spot Marker (Konstantinović et al., 2008). Monitoring of this species was also done because of the occurrence of retro vegetation after mowing. During vegetation period, this allergenic weed species was controlled by multiple mowing, and rough ruderal sites outside settlements were treated by glyphosate at a rate of kg ha -1. In the period at the Faculty of Agriculture the concentration of pollen was monitored by Rotorod pollen sampler spore collector. The concentration of pollen was calculated by the formula for Rotorod sampler applied in Peter Engle Science Centre (Anonymus, 2009). Results and discussion Three years lasting monitoring studies suggested that A. artemisiifolia L. control led to significant reduction of its abundance. Recommended mechanical control measures are predominantly cultivating in germination phase, maintenance of crops without weeds, as well as mowing of non-arable land (Konstantinović, 2008). Danger of A. artemisiifolia is in its abundance, huge seed production and its allergen effect on people (Konstantinović et al., 2008). During 2008 control of A. artemisiifolia on the territory of Vojvodina was executed by help of the Province s authorities in 42 municipality where it was controlled mechanically and chemically on the area of over ha. Monitoring of this species confirmed occurrence of retro vegetation. Only several species belonging to the family Asteraceae are relevant as allergenic source, and the most important are A. artemisiifolia and Artemisia vulgaris. Mapping during the examination period revealed presence of ragweed in over 200 locations in 21 urban area of Novi Sad. Mapping, determination of it s abundance and coverage in the period April-October in the three-years studies, revealed that the highest abundance of A. artemisiifolia was 50 plants m 2. For each city area were made maps in the program Ambrosia Spot Marker (Pictures 1 and 2). 159

164 Konstantinović et al plants/m plants/m 2 over 20 plants/m 2 Picture 1. The map of ragweed distribution on the territory of Sangai, 2008, in Ambrosia Spot Marker Softver 0-10 plants/m plants/m 2 over 20 plants/m 2 Picture 2. The map of ragweed distribution on the territory of Petrovaradin, 2010, in Ambrosia Spot Marker Softver 160

165 Mapping of invasive species Ambrosia artemisifolia L. by ambrosia spot marker.. In Table 1 are given total areas under ragweed on which mechanical and chemical control was performed. Table 1. Total areas on which Ambrosia artemisiifolia L. control was performed during Locality Mechanical control Chemical control (m²) (m²) Petrovaradin Rumenka Kisaĉ Stepanovićevo Ĉenej Pejićevi Salaši Kać Budisava Kovilj Mišeluk Šangaj Veternik Begeĉ Futog Highway and surrounding Dumps Surrounding of Liberty Bridge Total Total (Mechanical+chemical) In the period June September pollination of allergenic plants is the highest. Allergenic weed species Ambrosia artemisiifolia L. in average per plant may produce 2.5 up to 8 x 10 9 pollen grains during 2 to 3 months of pollination during vegetation period (Laaidi et al., 2003), and one g of Ambrosia artemisiifolia L, grain contains millions of pollen grains (Bagarozzi and Travis, 1998). Pollen can be found at height up to 5000 m above see level and up to 160 km away from the infested area (Járainé, 2003). In the summer 2008, they were found in much smaller amounts (per 191 m 3 air). In summer 2009 measurements of the number Ambrosia artemisiifolia L. pollen grains showed that the maximum number of pollen was in the second half of August in the amount of 783 pollen grains per m 3 of air and at the beginning of September, in the amount 705 pollen grains per m 3 of air (Figure 1). 161

166 Konstantinović et al. Measured pollen concentrations manifold exceed the tolerance level and present extremely high and dangerous concentrations for human health. Figure 1. Ambrosia artemisiifolia L. pollen concentration in the air in the period Conclusion Invasive weed species Ambrosia artemisiifolia L. is widely distributed on the territory of the City of Novi Sad. It builds huge and compact communities, predominantly at ruderal sites. Distribution sites of invasive weed species are ruderal sites, yards, construction sites, and suburbs of cities, sites along the roads and railway lines, dams and the edges of forests. In the three years, lasting period ( ), at the territory of the City of Novi Sad, A. artemisiifolia L. was determined on over 200 localities in 21 city zones. Mapping, determination of abundance and distribution of this invasive weed species was performed during vegetation season for each month from April to October, and the highest number of A. artemisiifolia L. was 50 individuals per m 2. Control was performed on around 900 ha on annual level, and monitoring confirmed occurrence of retro vegetation. Recommended mechanical measures such as mowing, drilling in the phase of germination, and chemical control measures that included application of glyphosate at a rate of kg ha -1, resulted in significant reduction of invasive weed species on the territory of the City of Novi Sad. During period of study at the Faculty of Agriculture in Novi Sad pollen concentrations in the air of allergen weed species Ambrosia artemisiifolia L. were monitored. In 2009, the highest number of pollen grains was found in the second half of August in the amount of 783 pollen grains per m 3 of air, and in 2008, the lower number of pollen grains was established. 162

167 Mapping of invasive species Ambrosia artemisifolia L. by ambrosia spot marker.. References ANONYMUS (2009). Center for Pollen Studies. Available from: BAGAROZZI D. A., TRAVIS J. (1998). Ragweed pollen proteolytic enzymes: possible roles in allergies and asthma. Phytochemistry 47: BRAUN-BLANQUET, J. (1951). Pflanzensoziologie. Wien, Osstereich. IGIĆ R., BOŢA I., ANAĈKOV G., VUKOV D. (2005). Atlas alergijskih biljaka Novog Sada. Prirodno-matematiĉki fakultet u Novom Sadu, Novi Sad. JÁRAINÉ M. (2003). Pannon Encyclopedy. Flora of Hungary. (Pannon Enciklopédia Magyarország növényvilága). Budapest: Ubris Könyvkiadó. JAUZEIN PH. (1998). Bilan des especes naturalisees en France mediterraneenne. In; Proceeding 6 th Mediterraneen Symposium EWRS, Montpellier, France, KONSTANTINOVIC B. (2008). Korovi i njihovo suzbijanje. Poljoprivredni fakultet, Novi Sad. KONSTANTINOVIĆ B., MESELDŢIJA M., KONSTANTINOVIĆ BO. (2008). Mapiranje vaţnih invazivnih korova i njihovo suzbijanje. Acta herbologica, Vol.17 (N.2), 53. LAAIDI M., THIBAUDON M., BESANCENOT P. (2003). Two statistical approaches to forecasting the start and duration of the pollen season of Ambrosia in the area of Lyon (France). Internat. J. Biometeorol. 48: MACK, R.N., SIMBERLOFF, D., LONSDALE, W.M., EVANS, H., CLOUT, M., AND BAZZAZ, F.A. (2000). Biotic invasions: Causes, epidemiology, global consequences, and control, Ecol. Appl., Vol.10 (No.3), 689. MAILLET J., LOPEZ-GARCIA C. (2000). Wheat criteria are relevant for predicting the invasive capacity of a new agricultural weed? The case of invasive american species in France. Weed Research, Vol.40, MALY K. (1940). Notizen zur Flora von Bosnien-Herzegovina. Glasnik zemaljskog muzeja za Bosnu i Hercegovinu, Sarajevo, II, 1-2. PRISZTER, SZ. (1960): Adventiv gyomnovenyeink terjedese. A Keszthelyi Mezogazdasagi Akademia Kiadvanyai. Mezogazdasagi Kiado. Budapest. RAVINDER K.K., SHIBU J., HARMINDER P. S., DAIZY R. B. (2009). Invasive Plants and Forest Ecosystems. CRC Press. New York. SLAVNIĆ Ţ. (1953). Prilog flori našeg Podunavlja. Glasnik biološke sekcije. Serija II, bt 4-6. Zagreb. VRBNIĈANIN S., JANJIĆ V. (2003). Uticaj abiotskih faktora na sastav korovske vegetacije strnih ţita. Herbologia,Vol.4 (No.l),

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169 Herbologia Vol. 12, No. 1, 2011 HORIZONTAL AND VERTICAL SEED DISTRIBUTION UNDER DIFFERENT FIELD CROPS Branko Konstantinović, Maja Meseldţija, Milena Korać, Nataša Mandić Faculty of Agriculture, Trg Dositeja Obradovica 8, Novi Sad Abstract Soil surface contains huge amount of seed of different weed species. By examination of weed seed distribution in the soil, it can be predicted which weeds will occur under different crops and to what extent. Detailed data analysis enables determination of timely soil tillage, as well as herbicide use. In the period , the weed seed bank was studied in different localities on the territory of Vojvodina (Krivaja, Ratkovo, Zmajevo, Baĉ, and Despotovo). Soil samples were collected from fields under different crops (soybean, sugar beet, maize, clover and sunflower). The sampling was performed diagonally in four replications from several arable depth layers of 0-10, and cm. Each sample was sieved through the system of cooper sieves of different diameter, according to the method of Conn (1987). After extraction from the samples, weed seeds were determined (Skender et. al., 1998; Kronaveter and Boar, 1994) and abundance of weed seed per m 2 was established for all three studied soil layers. The most abundant weed species in the weed seed bank under all studied crops were: Amaranthus retroflexus, Chenopodium album, Datura stramonium, Polygonum lapathifolium and Solanum nigrum, while less abundant were seeds of: Echinochloa cruss-galli, Euphorbia helioscopia, Sinapis arvensis, Sorghum halepense and Stachys annua. The highest abundance of weed seed was found at locality Zmajevo under sunflower crop in the soil layer of 0-10 cm, in the amount of seeds per m 2. At locality Krivaja, under soybean crop, the highest number of seeds was recorded in layers of and 20-30, in the amount of and seeds per m 2, respectively. The results were statistically processed and it was calculated that the highest coefficient of variance, i.e. the maximum deviation between number of seeds of weed species per soil layers was % at locality Despotovo. Keywords: seed distribution in the soil, Vojvodina, weed abundance Introduction In the arable soil layer, weed seed bank is distributed horizontally and vertically. Soil type, tillage, and crop species, have great influence on the

170 Konstantinović et al. amount of weed seed in the soil. The soil seed bank is a product of the past, and represents the potential future of the above ground plant community (Swanton & Booth, 2004). During harvest on arable land, weed seeds remain on the plant, and tillage brings it to the surface, where it represents future seed bank (Konstantinović, 2008). There is a great interest in prediction of presence and spaciousness of the species from studying of the soil properties (Streibig et al., 1984; Andreasen et al., 1991; Milberg and Hallgren, 2000). It is known that soil properties and the amount of weeds spatially change agricultural fields. It is therefore necessary to establish timely the size of the weed seed bank. (Walter et al., 2002). The density of weed seeds, as well as the amount in great extent depends upon soil type, previous crops, tillage and of the herbicide application (Konstantinović et al, 2008). Most of weed seeds are located in the top 10 cm of soil, which is part of the arable area. The study of weed seeds and establishment of their number is very important because it can help in their control and timely determination of weed control measures and herbicide application. In the period , study of seed banks in different localities on the territory of the Autonomous Province of Vojvodina, under different field crops such as soybean, sugar beet, maize, clover and sunflower gave an insight into distribution of dominant weed species in the soil layers of 0-10, and cm. Materials and methods In the period , soil samples were taken at different localities on the territory of AP Vojvodina, i.e. Krivaja, Ratkovo, Zmajevo, Baĉ and Despotovo from the soil under soybean, sugar beat, maize, clover and sunflower crops. The samples were taken from different soil layers of 0-10 cm, and cm (Conn, 1987; Sharatt, 1998). Sieving of the samples in laboratory conditions was performed through sieves of different diameters, after which followed separation and weed seed determination by use of manuals (Skender et al., 1998; Kronaveter and Boţa, 1994). The obtained results were processed in the program Statistica 7. The aim of the paper was to study composition of weed seed bank in arable soil layer under different field cultures. Results and discussion In fields under maize located at Despotovo, in the soil layer of 0-10 cm, a higher number of seeds of weed species Chenopodium album L. was determined (716 of seeds per m²) and Amaranthus retroflexus L. (281 seeds per m²). In the soil layer of cm domination of seeds of weed species 166

171 Horizontal and vertical seed distribution under different field crops Chenopodium album L. (1.866 seeds per m²) and Amaranthus retroflexus L. (613 seeds per m²) was established, while in the soil layer of cm the highest number of seeds of weed species Amaranthus retroflexus L. (1.329 seeds per m²) and Chenopodium album L. (1.304 seeds per m²) (Figure 1) were also determined Figure 1. Seed of weed species in fields under maize located at Despotovo in different soil layers In fields under sugar beet located at Baĉ in the layer of 0-10 cm revealed the highest number of weed seeds of the species Amaranthus retroflexus L. (2.761 seeds per m²) and seeds of weed species Datura stramonium L. (358 seeds per m²). In the layer of cm, the higher number of seeds of the species Amaranthus retroflexus L. (2.941 seeds per m²) and Datura stramonium L. (537 seeds per m²) were found, and in the soil layer of cm huge number of seeds of weed species Amaranthus retroflexus L. in the amount of and Datura stramonium L. in the amount of 818 seeds per m² were found (Figure 2). 167

172 Konstantinović et al Figure 2. Seed of weed species in fields under sugar beet located at Baĉ in different soil layers In fields under wheat located at Zmajevo, in soil depth of 0-10 cm higher number of seeds of weed species Amaranthus retroflexus L. (4397 seeds per m²) and Datura stramonium L. (2.837 seeds per m²) was determined. In the soil layer of cm, higher number of seeds of weed species Amaranthus retroflexus L. (2.454 seeds per m²) and Datura stramonium L. (2.301 seeds per m²) was found. In the soil layer of cm, a higher number of seeds of weed species Amaranthus retroflexus L. (2.275 seeds per m²), as well as seeds of Datura stramonium L. (1.713 seeds per m²) (Figure 3) was determined Figure 3. Seed of weed species in fields under sunflower located at Zmajevo in different soil layers 168

173 Horizontal and vertical seed distribution under different field crops Figure 4. Seed of weed species in fields under clover located at Ratkovo in different soil layers In fields under clover located at Baĉ, in the layer of 0-10 cm, a higher number of seeds of weed species Amaranthus retroflexus L. (2.352 seeds per m²), Capsicum annum L. (588 seeds per m²) i Chenopodium album L. (460 seeds per m²) was recorded. In the soil layer of cm, a higher number of Amaranthus retroflexus L. seeds (1.380 seeds per m²), Chenopodium album L. (588 seeds per m²) and Rumex crispus L. (486 seeds per m²) was found. In the soil layer of cm, a higher abundance of seeds of weed species Chenopodium album L. (1.559 seeds per m²), Amaranthus retroflexus L. (1099 seeds per m²) i Rumex crispus L. (537 seeds per m²) was found (Figure 4) Figure 5. Seed of weed species in fields under soybean located at Krivaja in different soil layers 169