Screening for Leaf Spot Resistance in Hard Red Spring Wheat

Transcription

1 Research Question 1) To screen elite wheat germplasm and recently released wheat cultivars to tan spot, Stagonospora nodorum blotch and Septoria tritici blotch in greenhouse and field tests. 2) To identify resistant sources/genes effective against the leaf spotting disease complex. 3) To determine the chromosomal location of major genes controlling resistance to leaf spotting diseases 4) To provide breeders with sources of resistance and genetic information to allow them to transfer leaf spotting resistance into the elite spring wheat. Results Screening for Leaf Spot Resistance in Hard Red Spring Wheat Majority of the 126 genotypes showed susceptibility to one or more races/pathogens causing leaf spots. A limited number (n=10) of genotypes showed resistance to both tan spot and septoria nodorum blotch (Table 1). Three recently released varieties, Trooper, Knudson, and Oklee and two advanced breeding lines, N and MN03291, were resistant to all races of P. tritici-repentis and S. nodorum tested. Additionally the above five genotypes are resistant to P. tritici-repentis toxin Ptr ToxA isolated from race 2 and to culture filtrates produced from P. tritici-repentis race 5, containing Ptr ToxB, and P. nodorum isolate Sn2000. The above five genotypes are well adapted to the northern plains of USA and can be successfully used in various wheat breeding programs. In order to broaden the genetic base of resistance to leaf spots, the resistance from breeding lines 92MREHTR28B, CIMMYT # 18, 2000 Spelt # 20, and Intros # 7 can also be used. These lines show high resistance to the races/pathogens/toxins tested, however; these lines may not adapted to northern Great Plains of USA hence may require multiple backcrosses to have germplasm with acceptable agronomic and quality traits. All durum lines screened were susceptible; however, a tetraploid accession, T. turgidum # 283 that gave consistent resistance to P. tritici-repentis races 2, 3, and 5, and P. nodorum. Additionally, this line is also resistant to Ptr ToxA (race 2) and culture filtrates of P. tritici-repentis race 5 and P. nodorum isolate Sn2000. Disease evaluation of the 126 wheat genotypes to Septoria tritici blotch is in progress and preliminary results indicate that majority of the P. K. Singh, Department of Plant Sciences, NDSU genotypes are susceptible although some genotypes show resistance. Six replicates of the 126 wheat genotypes were planted at NDSU field research plots at Fargo and Prosper, ND in disease nurseries to evaluate for resistance to tan spot and stagonospora nodorum blotch. Artificial inoculation was done at both the nurseries. At Prosper, additional misting was provided to enhance disease development in the nurseries. Unfortunately due to extremely unfavorable weather conditions this year, there was no disease development at Fargo and Prosper; hence the field nurseries were discarded. This nursery acted as seed increase source for doing replicated disease tests in the coming years. DNA extraction and quantification of the 126 wheat lines/varieties has been completed. Molecular markers linked to leaf spotting resistance identified in previous studies have been selected. Presently these molecular markers are being tested on the wheat genotypes to confirm for the presence of the known resistance genes. Additionally, genetic similarity/diversity of wheat genotypes from the northern great plains of USA to leaf spots would also be attempted. Studies on chromosomal location of major genes controlling resistance to tan spot and Stagonospora nodorum blotch was done utilizing the Langdon-T. dicoccoides (Israel A) substitution lines. Plants were evaluated for disease reaction at the two leaf stage under controlled environmental conditions. Based on the reaction of the Langdon-T. dicoccoides (Israel A) substitution lines, chromosomal location of the resistance genes for tan spot caused by P. tritici-repentis races 1 and 2, and 3 and 5 was determined to be on chromosomes 5B and 3B, respectively. Resistance to toxin Ptr ToxA, produced by P. tritici-repentis race 2, was located on chromosome 5B while toxin Ptr ToxB, produced by P. tritici-repentis race 5, failed to induce any disease in the tetraploid genotypes including Langdon-substitution lines. Resistance to Stagonospora nodorum blotch caused by P. nodorum isolate Sn2000 was located on chromosome 5B. These novel findings will further assist breeders in the development of leaf spot resistant wheat varieties for the northern plains of USA. Page 10

2 breeding material and the resistance genes which Application/Use need to be added in order to develop leaf spot resistant varieties. The information on the disease reaction of the elite wheat breeding germplasm to each of the toxins/ pathogens/races causing the leaf spotting disease complex will provide vital information to wheat breeders in developing resistant varieties. This ongoing study on completion will determine the different susceptibility genes present in our elite germplasm and the resistance genes that need to be added. The identification of resistant lines/genotypes and its use in development of resistant wheat varieties will provide efficient and economical management of leaf spots thus minimizing losses in grain yield and quality thereby improving the economic efficiency of wheat production. With the availability of resistant varieties, the use of fungicides, a practice not often environmentally safe and cost effective, would not be necessary. Validation of already identified molecular markers will enhance marker-assisted selection for disease resistance and fasten varietal development process. Additionally, identification of chromosomal location of various resistance genes for leaf spotting diseases will further fasten the development of leaf spot resistant varieties. Materials and Methods An elite germplasm of 126 genotypes comprising of hard red spring, white, and durum wheat varieties and advanced breeding materials from NDSU, U of MN, SDSU and other wheat breeding programs were evaluated in greenhouse with individual races 2, 3, and 5 of Pyrenophora tritici-repentis prevalent in the northern Great Plains of USA. Additionally the wheat genotypes were tested with P. tritici-repentis produced toxins Ptr ToxA and Ptr ToxB. The wheat germplasm was also screened for resistance to stagonospora nodorum blotch caused by spore suspension and culture filtrate of P. nodorum isolate Sn2000. Presently screening for resistance to septoria tritici blotch is in progress. Additionally these 126 wheat genotypes were planted replicated trials in disease nurseries at Fargo and Prosper, ND, to evaluate for resistance to tan spot and Stagonospora nodorum blotch. However, field evaluation in 2006 was unsuccessful due to poor disease development conditions. DNA extraction and quantification of the 126 wheat lines/varieties has been done and presently molecular markers linked to leaf spotting resistance genes are being tested on these genotypes to confirm the presence of resistance genes in these lines. These greenhouse and molecular screenings will determine the different susceptibility genes present in our elite Economic Benefit to a Typical 500 Acre Wheat Enterprise Leaf spots on average cause yield losses from 10-15% and cause loss in grain quality by grain shriveling, dark smudge and black point. With the completion of this project, the wheat breeders will get the genetic information and the resources needed for development of leaf spot resistant varieties. Resistant durum and common wheat varieties, in conjunction with crop rotation, will provide an enhanced protection against leaf spotting diseases thereby reducing yield and quality losses. This will enhance the economic returns through wheat production to farmers. Related Research Previous studies have involved screening for new sources of resistance to leaf spots in greenhouse or field evaluations (1,9), inheritance of resistance (8,11,12) and race structure of the pathogens (2,10). Significant efforts have been made in identifying molecular markers for the resistance genes (3,5,6,7) and in molecular biology of host-pathogen interaction (4). Major disease resistance breeding efforts for the leaf spotting diseases have involved multilocation artificial inoculated field screening (13). Additionally, researchers have studies the role of toxins in disease development (7,8,9). Recent genetic studies reveal that resistance to leaf spotting diseases in wheat is controlled by major genes i.e. tan spot is controlled by three major resistance genes (8), stagonospora nodorum blotch is controlled by one or two genes (11) and septoria tritici blotch is controlled by two or three genes (12). The total number of resistance genes involved in leaf spot resistance for the three diseases are between 6-8. Molecular markers linked to four of these major genes have been identified (3,5,6,7) and they will be used in this project to help pyramid the resistance genes. References 1. Alam, K.B. and J.P. Gustafson Plant Breed. 100: Ali, S. And L.J. Francl Plant Dis. 87: Cao, W., G.R. Hughes, and Z. Dong Theor. Appl. Genet. 102: Page 11

3 4. Ciuffetti, L.M. and R.P. Tuori Phytopathol ogy 89: Faris, J.D., J.A. Anderson, L.J. Francl, and J.D. Jordahl Phytopatholgy 86: Faris, J.D., J.A. Anderson, L.J. Francl, and J.D. Jordahl Theor. Appl. Genet. 94: Friesen, T.L. and J.D. Faris Theor. Appl. Genet. 109: Gamba, F.M.. and L. Lamari Can. J. of Plant Pathology 20: Lamari, L. and C.C. Bernier Can. J. of Plant Pathology 11: Lamari, L., J. Gilbert, and A. Tekauz Can. J. of Plant Pathology 20: Ma, H. and G.R. Hughes Genome 38: McCartney, C.A., A.L. Brule-Babel, and L. Lamari Phytopathology 92: Raymond, P.J., W.W. Bockus, and B.L. Norman Phytopatholgy 75: APPENDIX Table 1. Reaction of 126 Elite wheat germplasm to P. tritici-repentis spore suspension of races 2, 3, and 5 and toxins Ptr ToxA and Ptr ToxB, P. nodorum (SNB) isolate Sn2000 (spore) and its culture filtrate (CF) and M. graminicola (STB) isolate Ma (spore). S.N. Page 12 Genotypes scored to Race 2 Race 3 Race 5 Tox A Tox B Spore CF 1 OXEN 3.5 N 1.8 R 1.9 R MS 2 INGOT 3.5 N 2.3 C 2.8 C MS 3 NORPRO 1.9 R 1.7 R 1.4 R MS 4 PARSHALL 3.1 N 1.6 R 3.8 C MS 5 REEDER 2.5 N 1.5 R 3.9 C MR 6 ALSEN 3.5 N 1.9 R 2.0 R MS 7 KNUDSON 1.6 R 1.6 R 1.8 R MR 8 HANNA 3.0 N 3.1 C 3.8 C MR 9 BRIGGS 2.2 N 2.4 C 2.5 C MR 10 GRANITE 1.9 R 2.2 C 2.6 C MS 11 OKLEE 1.5 R 1.4 R 1.3 R MS 12 DAPPS 2.1 N 2.8 C 4.0 C MR 13 STEELE-ND 3.7 N 3.0 C 4.2 C MS 14 FREYR 2.2 N 1.6 R 2.0 R MS 15 TROOPER 2.0 R 2.0 R 1.6 R MR 16 BANTON 3.1 N 3.4 C 3.9 C MS 17 SATURN 2.9 N 2.1 C 1.6 R MS 18 POLARIS 2.2 N 1.6 R 2.6 C MS N 2.4 C 1.9 R MS 20 VERDE 2.5 N 2.0 R 2.8 C MR 21 KEENE 3.6 N 1.9 R 4.3 C R 22 BUTTE N 1.9 R 4.2 C MR 23 McNEAL 2.9 N 1.3 R 1.6 R MS 24 WALWORTH 3.1 N 1.7 R 1.9 R MS 25 DANDY 3.4 N 2.0 R 2.0 R MR 26 GRANGER 2.9 N 2.1 C 2.6 C S 27 SD N 3.1 C 3.2 C MS continued...

4 S.N. Genotypes scored to Race 2 Race 3 Race 5 ToxA ToxB Spore CF 28 SD N 3.1 C 3.1 C MS 29 SD N 1.8 R 2.1 C S 30 SD N 2.3 C 1.9 R MS 31 SD N 3.1 C 3.9 C MS 32 SD N 2.6 C 2.8 C MS 33 SD N 2.5 C 2.5 C MS 34 SD N 2.0 R 4.1 C MS 35 SD N 2.1 C 2.2 C MR 36 SD N 1.8 R 2.5 C MS 37 SD N 1.8 R 3.9 C MR 38 BZ W 3.0 N 2.0 R 2.9 C MR 39 CA N 2.8 C 1.8 R MR 40 CA W 3.0 N 1.8 R 1.8 R R 41 N R 1.4 R 1.8 R MS 42 96S R 1.5 R 2.5 C MS 43 98S N 1.3 R 3.6 C S 44 98S N 1.8 R 2.1 C S 45 97S R 2.5 C 2.2 C MR 46 MN N 1.5 R 3.8 C MS 47 MN N 1.8 R 2.2 C MS 48 MN N 1.9 R 4.0 C MS 49 MN N 2.5 C 4.3 C MR 50 MN N 1.7 R 1.7 R R 51 MN N 2.2 C 3.9 C MS 52 MN N 2.3 C 1.9 R S 53 MN N 1.8 R 1.6 R S 54 MN N 1.8 R 3.8 C MS 55 MN N 1.8 R 2.4 C MS 56 MN01333-A 3.1 N 1.7 R 2.0 R MS 57 MN N 2.7 C 3.7 C MS 58 MN N 1.8 R 3.8 C S 59 MN N 1.5 R 1.5 R MS 60 MN N 1.8 R 1.8 R MR 61 MN N 1.9 R 3.9 C MR 62 MN N 1.9 R 2.3 C MS 63 MN02296-A 2.0 R 1.5 R 3.4 C S 64 MN N 3.0 C 1.8 R MS 65 MN N 2.0 R 1.7 R MS continued... Page 13

5 S.N. Genotypes scored to Race 2 Race 3 Race 5 ToxA ToxB Spore CF 66 MN N 2.0 R 1.6 R MS 67 MN N 1.8 R 3.6 C MS 68 MN N 1.9 R 3.9 C MR 69 MN N 3.0 C 4.0 C MR 70 MN N 1.7 R 1.6 R MS 71 MN R 1.4 R 1.9 R R 72 MN R 1.3 R 3.5 C MS 73 MN N 1.9 R 2.5 C MR 74 WA N 2.1 C 1.7 R MR 75 WA N 2.3 C 1.6 R MR 76 MT N 2.0 R 2.0 R MR 77 MT N 1.9 R 4.0 C MS 78 ND N 1.9 R 3.9 C MS 79 ND N 1.7 R 1.7 R MS 80 ND N 2.0 R 4.3 C MS 81 ND N 1.8 R 4.0 C MS 82 ND N 1.7 R 4.2 C MR 83 ND N 1.7 R 4.4 C MR 84 ND N 2.1 C 4.3 C MS 85 ND N 1.5 R 4.0 C MR 86 ND N 1.8 R 2.3 C MS 87 ND N 1.5 R 3.6 C MR 88 ND N 1.7 R 2.1 C MS 89 ND R 2.1 C 3.7 C MS 90 ND N 1.6 R 3.5 C MS 91 ND N 1.5 R 1.9 R MR 92 ND R 2.1 C 3.9 C MS 93 ND N 1.8 R 3.9 C MS 94 ND N 1.6 R 3.9 C MS 95 ND R 1.4 R 3.4 C MR 96 NDSW N 2.2 C 4.1 C MS 97 NDSW N 3.0 C 2.6 C MS 98 NDSW N 2.4 C 4.2 C S 99 NDSW N 1.8 R 4.2 C MS 100 NDSW N 2.6 C 2.2 C MS 101 ERIK (Check) 1.3 R 1.3 R 1.5 R S 102 GLENLEA (Check) 4.3 N 2.0 R 1.9 R MS 103 6B-365 (Check) 1.7 R 4.1 C 1.9 R MR 104 6B-662 (Check) 1.7 R 1.7 R 4.0 C MR 105 ND 495 (Check) 4.5 N 2.3 C 2.5 C MS continued... Page 14

6 S.N. Genotypes scored to Race 2 Race 3 Race 5 ToxA ToxB Spore CF 106 CONWAY (Check) 4.0 N 1.8 R 4.1 C S 107 KATEPWA (Check) 4.0 N 1.8 R 4.4 C MS 108 KENYON (Check) 4.3 N 2.4 C 3.8 C MS 109 COULTER (Check) 4.3 N 4.1 N 4.3 N MS 110 4B-160 (Check) 1.7 R 2.9 N 2.5 N MR 111 T. turgidum # R 1.4 R 1.4 R R 112 Intros # R 1.3 R 1.3 R R MREHTR 28B 1.6 R 1.3 R 1.3 R R Spelt # R 1.2 R 1.5 R MR 115 CIMMYT L # R 1.3 R 1.4 R MR 116 SALOUMINI 1.4 R 1.4 R 1.3 R MR 117 MOUNTRAIL 2.2 N 3.2 N 2.2 N MS 118 BEN 3.8 N 3.6 N 2.3 N R 119 LEBSOCK 2.7 N 3.0 N 1.9 R MR 120 PIERCE 3.6 N 3.2 N 2.0 R MR 121 MAIER 3.1 N 2.7 N 2.5 N MR 122 PLAZA 3.0 N 2.4 N 2.7 N MS 123 DILSE 3.2 N 2.9 N 3.3 N S 124 D N 3.1 N 2.5 N R 125 D N 3.0 N 3.0 N MS 126 D N 2.5 N 3.0 N MR Disease rating (1-5 lesion type scale) is mean of six replicates with each replicate having four plants The disease Septoria tritici blotch has been screened once wherein R=Resistant, MR=Moderately resistant, MS= Moderately susceptible, and S=Susceptible Recommended Future Research 1. Continuing screening of the elite germplasm with M. graminicola, cause of septoria tritici blotch. 2. Molecular markers will be used to confirm the presence of resistance genes in the lines/cultivars. 3. Screening in multi-location field nurseries under artificial inoculation at seedling and adult plant stages in coming years. 4. Writing of final project report and providing technical and extension information to relevant authorities. Publications Singh, P.K., M. Mergoum, S. Ali, T.B. Adhikari, Elias, J.A. Anderson, K.D. Glover and W.A. Berzonsky Evaluation of elite wheat germplasm for resistance to tan spot. Plant Disease 90: Singh, P.K., M. Mergoum, T.B. Adhikari, E.M. Elias, and S.F. Kianian. Chromosomal location of genes for resistance to tan spot and Stagonospora nodorum blotch resistance genes in tetraploid wheat. Euphytica (Accepted). Singh, P. K., M. Mergoum, T.B. Adhikari, E.M. Elias, and S.F. Kianian Chromosomal location of major genes for resistance to tan spot and Stagonospora nodorum blotch in tetraploid wheat. Poster Presentation. Joint Annual Meeting of APS/CPS. 29th July to 2nd August. Quebec City, Canada. Phytopathology 96: S108 (Abs). Page 15