COMPETITIVE ABILITY OF CAPSICUM ANNUUM L. RELATIVE TO THE WEED AMARANTHUS LIVIDUS L.

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1 Journl of Hortiulturl Rsrh 216, vol. 24(1): DOI: /johr COMPETITIVE ABILITY OF CAPSICUM ANNUUM L. RELATIVE TO THE WEED AMARANTHUS LIVIDUS L. Asstr OMEZINE 1 *, Jim A. TEIXEIRA DA SILVA 2 ** 1 Institution of Agriulturl Rsrh n Highr Eution, Tunis, Tunisi 2 Rtir, Miki-ho, Jpn Riv: Sptmr 215; Apt: April 216 ABSTRACT Amrnthus livius is th most frquntly rport troulsom w in th proution of Cpsium nnuum in som rgions us it is n ggrssiv invr, iffiult to ontrol, n rus yil signifintly. Th ffts of A. livius on th growth of C. nnuum Bklouti wr vlut unr grnhous onitions. Thr xprimnts wr onut to trmin th fft of A. livius on th iomss umultion of C. nnuum slings for 4 ys. In n itiv xprimnt, to on C. nnuum sling n 1, 2, 3 or 4 A. livius slings wr grown pr pot. Th son xprimnt ws stlish to ssss C. nnuum intromptition using from on to six plnts pr pot s th nsity. In rplmnt xprimnt, C. nnuum n A. livius slings wr trnsplnt into pots with iffrnt proportions of oth plnts (1/5, 2/4, 3/3, 4/2, 5/1). Comptition y A. livius ru C. nnuum plnt ry wight y s muh s 93%. Howvr, C. nnuum h littl fft on A. livius, ruing ry wight y 31.3% t 5:1 rtio of C. nnuum: A. livius. Rltiv yil nlysis twn C. nnuum n A. livius monstrt th omptitiv vntg of C. nnuum ovr A. livius. Th rltiv rowing offiint of oth plnts hng signifintly in th prsn of th othr plnt, t ny rtio. Th ggrssivity of C. nnuum ws highr t its lowr proportion n C. nnuum ws mor ggrssiv towrs itslf thn towrs A. livius whn its nsity inrs. Ky wors: ggrssivity; lllopthy; omptition; rltiv rowing offiint; rltiv yil; ws INTRODUCTION In Tunisi, Cpsium nnuum L. (Soln), or ppprs in gnrl, is n importnt ommril rop grown on wi rng of soils t ltitus vrying from s lvl to 2 m, oth for intrnl onsumption n for xport. C. nnuum is rnk fifth (in trms of rg) ftr tomto, wtrmlon, potto n onion (Boughll & El Mhjou 25). In Afri, Tunisi is th thir lrgst prour of C. nnuum ftr Nigri n Egypt, n th thir lrgst xportr (in trms of tonng) ftr Moroo n South Afri (FAO 213). In 28 n 21, Tunisi ws rnk 12 n 11, in trms of glol proution with worl rnk of 45 n 53, rsptivly in xport trms (FAO 213). Th yil of C. nnum in Tunisi vrgs 12.5 t/h, whih is rltivly low ompr to yil osrv in othr Mitrrnn ountris suh s Spin (35 t h -1 ), Itly (28 t h -1 ), Gr (23 t h -1 ), n Moroo (14 t h -1 ) (Boughll & El Mhjou 25). Ths low yils r u to iffiultis in stlishing ffiint ontrol msurs. On of th min prolms ffting rop yil n qulity is w intrfrn (Hgr t l. 22; Botright & MKissik 24). Svr w infsttions n ru yil y t lst 5-87% n som ws, mong thm Amrnthus livius, my t s ltrnt hosts of insts, psts n isss (Botright & MKissik 24). Efftiv w mngmnt is thus on of th mny ritil omponnts of sussful C. nnuum proution. Th gnus Amrnthus is rprsnt y pproximtly 6 spis (Holm t l. 1997; Wirsm & Lon 213), wily istriut in tropil, sutropil n tmprt rgions (Crvlho t *Corrsponing uthors: -mil: *sstr.omzin@yhoo.fr; **jimtx@yhoo.om Unuthntit Downlo Dt 1/23/19 8:5 AM

2 8 A. Omzin, J.A. Tixir Silv l. 26). A. livius is mong th most unnt ws ourring in n ffting vgtl rops, lwns, psturs, grns n row rops (Murphy t l. 21) throughout th wrm tmprt n tropil rgions of Nw n Ol Worls (Wirsm & Lón 213). It is rsponsil for signifint yil losss in mny rops, whih vris with th nsity of A. livius. For xmpl, th yil of C. nnuum ws ru y 67% whn it ompt with four A. livius plnts m -2 (Morls-Pyn t l. 22). In nothr unontroll stuy, thr A. livius plnts m -2 intrfr with C. nnuum, ruing yil y 33% (Morls-Pyn t l. 23). Mximum yil loss ws 65% whn six A. livius plnts wr grown pr m 2 or 3% with singl A. livius plnt m -2 (Morls- Pyn & Stll 22). Thos stuis, howvr, fil to ssss th rtio of C. nnuum: A. livius (i.., th nsity of on spis rltiv to th othr), n thus srv s th sis for this stuy with th hypothsis tht th growth n sussful survivl of on spis woul hng in th prsn of th othr. In Tunisi, n vn roun th worl, limit informtion is vill on hmil n iologil w ontrol, inluing tht of spifi ws lik A. livius (Murphy t l. 21). Howvr, th only msur to ontrol A. livius n othr ws in vgtl rop stns, inluing thos of C. nnuum, prtiulrly in low-inom ountris, is ulturl mthos, prtiulrly prioi hoing n hn pulling throughout th growing sson. This pross is lorious, strts rly in th sson whn th ws r smll n th pross is frquntly rpt throughout th sson. Thus, to fin mhnism tht is l to limit prtiulr plnts growth using plnt nsity oul thortilly ru, or rmov, th n for hmil ontrol, n srv s prtil, low-ost thniqu for rurl frmrs glolly. If our first hypothsis hl tru (i.., tht C. nnum oul ngtivly influn th growth of A. livius), it thn oms importnt to trmin th lvl of intrtion whn th rtio of h ws vri. Expt for th Morls-Pyn-ssoit pprs list ov, no systmti rsrh hs n onut thus fr to xplor th omptitiv hvior of C. nnuum towrs ws. Aginst this kgroun, lk of til informtion out th fft of A. livius on th growth of C. nnuum n losss us to growth, n th rpi spr of A. livius in vgtl proution systms in Tunisi, North Afri n lswhr roun th worl, this stuy st out to rss thr ky ojtivs, onut in thr sprt xprimnts: (1) to xmin th fft of A. livius nsity on C. nnuum growth uring th sling stg, whih is th most snsitiv growth stg; (2) to otin th pproprit plnt nsity of C. nnuum to minimiz intromptition; (3) to tst th omptitiv ility of C. nnuum towrs th w A. livius using rplmnt mtho. Th hop ws tht suitl C. nnuum : A. livius rtio oul foun to nsur mximum w ontrol t no ost, sin osts r tritionlly ssoit with hmil ontrol or wing. To tst ths ojtivs, iffrnt omptition inis wr mploy. MATERIALS AND METHODS To stuy intr- n intr-spifi omptition twn rop C. nnuum Bklouti n w A. livius, thr pot xprimnts wr prform unr grnhous onitions. Thy wr onut t th Suprior Institut of Agriulturl Sins (ISA) of Chott-Mrim (Souss, Tunisi) in th fll of 21 n rpt in 211. Th xprimntl units wr plsti ontinrs (8 m in imtr n 1 m p) fill with stnr hortiulturl potting mium (sn, mnur, prlit; 1 : 1 : 1, v / v). Bs on th prvious osrvtions, this ontinr siz ws hosn to provi unrstrit C. nnuum n A. livius growth for 4 ys ftr plnting. C. nnuum ss wr sown in stnr hortiulturl potting mium n trnsplnt t th tru two-lf stg into xprimntl ontinrs. A. livius ss wr ollt from lol fil stns in C. nnuum fils nr ISA. A. livius ss wr sown in xprimntl pots n thinn ftr mrgn to th numrs sri in Exprimnts 1 n 3. Th pots wr irrigt with 5 ml of potl wtr vry two ys from th strt to th n of th xprimnt. Th slinity (mss of issolv slts) of th wtr ws 1.2 g m -3. Aftr 4 ys sin psium trnsplnttion, th whol plnt ry wight (DW) ws trmin s xplin nxt. Th xprimntl sign ws ompltly rnomiz with fiv xprimntl units. Unuthntit Downlo Dt 1/23/19 8:5 AM

3 Comptition twn Cpsium nnuum n Amrnthus livius 81 In th itiv xprimnt (Exp. 1), on C. nnuum sling ws plnt pr pot, togthr with 1, 2, 3 or 4 A. livius slings, whih wr sp 2 m prt of C. nnuum sling. In th son xprimnt (Exp. 2), intromptition twn C. nnuum slings ws stui. In on pot 1, 2, 3, 4, 5 or 6 plnts wr grown. In th rplmnt xprimnt (Exp. 3), thr wr six plnts in on pot grown s mixtur of C. nnuum n A. livius slings in iffrnt proportions. Th following omintions wr vlut: (1) 1% C. nnuum (6 plnts/pot, s monoultur); (2) 83.3% C. nnuum (5 plnts/pot) % A. livius (1 plnt/pot); (3) 66.6% C. nnuum (4 plnts/pot) % A. livius (2 plnts/pot); (4) 5% C. nnuum (3 plnts/pot) + 5% A. livius (3 plnts/pot); (5) 33.3% C. nnuum (2 plnts/pot) % A. livius (4 plnts/pot); (6) 16.6% C. nnuum (5 plnts/pot) % A. livius (5 plnts/pot); (7) % C. nnuum (i.., n Amrnthus monoultur). Forty ys ftr trnsplnting C. nnuum, totl ry wight (DW) of C. nnuum n A. livius wr trmin, s xplin nxt. At 4 DAP, C. nnuum n A. livius iomss ws sprt. Roots of h plnt wr wsh gntly n thoroughly to rmov soil prtils so tht th root tissus rmin intt. DW ws trmin y rying th whol plnt in n ovn for 48 h t 8 C. Th rltiv prformn of h spis in th A. livius / C. nnuum omintion ws lult. Th rltiv yil (RY) of oth spis ws nlyz grphilly s sri y Wit (196) n Hrpr (1977). Th RY of A. livius (RY), th RY of C. nnuum (RY) n th totl rltiv yil (RYT) of oth spis wr lult sprtly oring to th following qutions (Hrpr, 1977): RY = yil of A. livius in th mixtur / yil of A. livius in monoultur; RY = yil of C. nnum in th mixtur / yil of C. nnuum in monoultur; RYT = RY + RY. A vlu of RYT = 1 inits tht C. nnuum n A. livius r mning th sm limiting rsours, RYT > 1 inits tht th two spis mk iffrnt mns on rsours, so omptition is voi n RYT < 1 inits tht thr is mutul ntgonism twn C. nnuum n A. livius ( Wit & Gourin 1978). Th rltiv rowing offiint (RCC) ws us to trmin th omptitiv ility of plnt to otin limit rsours whn grown in ommunity stting ompr to its ility to utiliz thos rsours whn grown in monoultur (Aminpnh 213). RCC ws lult for oth spis using th formul of Hoffmn n Buhlr (22): RCC = [(DW 1 5 / DW 5 1) + (DW 2 4 / DW 4 2) + (DW 3 3 / DW 3 3) + (DW 4 2 / DW 2 4) + (DW 5 1 / DW 1 5) + (DW 6 / DW 6)], whr DW n n is th DW of C. nnuum t rtio of n : n n DW n n is th DW of A. livius t iffrnt rtios. Thus, for xmpl, DW 1 5 / DW 5 1 = th DW of on Cpsium plnt n fiv Amrnthus plnts pr pot ivi y th DW of fiv Amrnthus plnts n on Cpsium plnt pr pot. Aoring to this finition, n RCC vlu > 1 signifis omptitiv vntg for C. nnuum ompr to A. livius n th lrgr th RCC vlu, th grtr th omptitivnss with C. nnuum. In ontrst, n RCC vlu of < 1 inits tht A. livius is mor omptitiv thn C. nnuum. An RCC vlu = 1 inits tht thr is no omptition or omptitiv vntg or isvntg twn oth spis. An inrs in th RCC vlu for spis s th proportion in th plnt mixtur inrss inits tht th rltiv omptitivnss of tht spis hs inrs (Morls-Pyn t l. 1999; Willims & MCrthy 21; Zrohntsv 212). Th thir inx ssss ws ggrssivity, whih is oftn us to trmin th omptitiv rltionship twn C. nnuum n A. livius in mix rop. Th ggrssivity of C. nnuum (A) ws lult s follows (MGilhrist & Trnth 1971): A = (DW Cpsium mix / DW Cpsium mono) (DW Amrnthus mix / DW Amrnthus mono), whr mix = mixtur of oth rops; mono = monoultur. If A =, thn oth rops r qully omptitiv; if A is positiv, thn C. nnuum is ominnt, n if A is ngtiv, thn C. nnuum is wk. Mn t sts of fiv rplits pr trtmnt in ompltly rnomiz sign n rpt twi wr sujt to on-wy nlysis of vrin (ANOVA), n mns wr sprt using Fishr s prott LSD t P =.5. Unuthntit Downlo Dt 1/23/19 8:5 AM

4 82 A. Omzin, J.A. Tixir Silv RESULTS AND DISCUSSION Aitiv xprimnt (Exp. 1) Mny ftors intrt to trmin th outom of omptition twn w n rop. Among ths ftors, w popultion nsity is mjor ftor. It is wll known tht rop nsity is importnt in limiting th omptitiv fft of ws. Mny othr ftors suh s soil typ n limt r yon th ontrol of frmrs ut rop nsity n mor sily ontroll. This stuy im to tk vntg of this si iologil ft to try n ontrol w (A. livius) in pppr proution systms using pot xprimnts. Slings in th most snsitiv growth stg of th plnt wr us. A. livius nsity h signifint fft on th DW of C. nnuum. DW umultion of C. nnuum rs s A. livius nsity inrs (Fig. 1). At ll nsitis, ithr on or four A. livius plnts ngtivly intrfr with n ru C. nnuum DW. This signifint rution of C. nnuum DW umultion t ll nsitis of A. livius suggsts tht th growth of C. nnuum plnts ws rtr y th onomitnt growth of A. livius. C. nnuum plnts umult mximum DW (2.1 g/pot) whn grown without A. livius whil lowst DW ws otin whn on C. nnuum plnt ws grown with four A. livius plnts (.46 g/pot). DW ws ru y out 8.8% u to omptition from on A. livius plnt n y 97.7% whn A. livius ws plnt t nsity of four plnts. This rltion implis tht on A. livius plnt t lowst nsity h grtr fft on C. nnuum growth thn on A. livius plnt t highr nsity. Wht is surprising is how so fw A. livius plnts/pot wr l to ru th growth of C. nnuum. It is likly tht not only omptition to nutrints ut lso othr typs of intrtions, inluing lllopthy, r involv. Th stuy of Brry t l. (26) show tht th nsity of A. livius, 1 to 2 plnts/m 2, us 1% yil rution of uumr. Also, Morls-Pyn n Stll (22) rport tht C. nnuum yil ws ru y 67% whn ompting with 6 A. livius pr squr mtr of fil throughout n ntir sson. Ths ffts of A. livius on th DW of C. nnuum rflt th omptitiv ility of A. livius (Proópio t l. 24) n lso its ggrssivnss (Silv t l. 29). Howvr, th umultion of A. livius DW ws moifi y its nsity n ws signifintly influn y th prsn of C. nnuum. Th highst umultion of A. livius DW ws osrv with four A. livius plnts ssoit with on C. nnuum plnt (52.33 g/pot) whil th lowst DW umultion (35.77 g/pot) ourr whn on A. livius plnt grw in th prsn of on C. nnuum plnt. Th DW umultion of iniviul C. nnuum plnts rs s A. livius nsity inrs ut lso, th DW umultion of iniviul A. livius plnt rs whn its nsity inrs (Fig. 2). Morovr, th totl mn DW / plnt (C. nnuum + A. livius) rs with inrs of A. livius nsity (Fig. 2). A similr rltion ws foun y Ronhi n Silv (26) in xprimnt with young off plnts growing with four ws. Intrspifi omptition xprimnt (Exp. 2) In th intrspifi xprimnt, n inrs in C. nnuum nsity inrs th DW umultion/pot up to fiv plnts/pot, ut rs rpily t six plnts/pot whil th DW umultion pr iniviul plnt ws not influn (Fig. 3), whih is typil rtion onrning yil of totl iomss. Agrwl t l. (27) not tht th yil of C. nnuum fruit inrs with its popultion growth up to 12, plnts/h rsulting in th highst mrktl yil ut not influning fruit mss; howvr, xing this popultion in th fil, fruit yil rs signifintly. Jolliff n Gy (1995) rport tht lf r, lf DW n shoot DW of C. nnuum rs signifintly s plnt popultion rh 11.1 plnts/m 2. In our stuy of intrspifi omptition, th osrv inrs in DW ws not proportionl to nsity. At high nsity of C. nnuum (6 plnts/pot), th totl DW of C. nnuum ws g/pot whrs t low nsity (1 plnt/pot), totl DW of C. nnuum ws 36.8 g/pot. In othr wors, ry wight of on C. nnuum plnt ws 27.4 g whn th nsity ws 6 plnts/pot n 36.8 g whn th nsity ws 1 plnt/pot. Jolliff n Gy (1995) show tht Unuthntit Downlo Dt 1/23/19 8:5 AM

5 Dry wight umultion of h spis pr pot (g) Comptition twn Cpsium nnuum n Amrnthus livius 83 high popultion (11.1 plnts/m 2 ) of C. nnuum rs iomss umultion pr unit ln r. Howvr, Hrpr (1977) foun tht th totl DW of Amrnthus rtroflxus / pot ws rltivly onstnt ut DW/plnt rs s A. rtroflxus nsity inrs. Dnsity ffts plnt rhittur, ltrs growth n vlopmntl pttrns n influns rohyrt proution n prtitioning. Plnt nsity my influn th vlopmnt n growth of vgtl rops, inluing onion (Asuzzmn t l. 215). Th plstiity of plnts is th pity for mrk vrition in n iniviul plnt phnotyp s rsult of nvironmntl influns on tht gnotyp uring vlopmnt in whih n iniviul plnt n grow lrgr or smllr pning on th rsours vill to it in its hitt (Pri t l. 23; Dkkr 211). High nsitis rs th solut growth rts of C. nnuum ut promot shoot iomss umultion pr unit ln r (Jolliff & Gy 1995). Sphi t l. (214) not tht plnt hight of C. nnuum hng signifintly in rspons to sping: losr sping rsult in mximum plnt hight, ut wir sping rsult in th highst numr of fruits. Quinto n Brrz (29) foun tht phnotypi plstiity of C. nnuum n fft y trtmnts, sin signifint fft of plnt nsity ws tt on stm imtr, lf r n lf numr, ut plnt hight ws lss plsti. In thir stuy, stm DW, lf DW, fruit DW n totl DW pr plnt rs s plnt nsity inrs. This phnotypilly plsti ility of C. nnuum s on morphologil trits (Lhi t l. 212) llows thm to rpily pt to hnging nvironmnts n nls thm to ontinu to surviv n rprou ross vril nvironmnts (Tétr-Jons t l. 211). Rplmnt xprimnt (Exp. 3) 1. Dry wight umultion Th DW umultion of C. nnuum (Cp/pot) inrs with th numr of pppr slings/pot (n proportion to A. livius) A similr trn onrning numr of plnts n proportion to C. nnuum ws shown for A. livius (Fig. 4). Th highst DW pr pot ws t highst proportion of pppr in th mixtur. Th umultion of DW y iniviul C. nnuum plnts inrs s its rtio in th mixtur rs. A similr trn ws osrv for A. livius in th mixtur. Th DW umultion of iniviul plnts, ithr Cpsium or Amrnthus, hng s thir rtio in th mixtur hng: from 1.43 to 3.58 g whn th proportion of Cpsium hng from 5 to 1 plnts/pot n from 6.37 to 1.72 g whn th proportion of Amrnthus hng from 1 to 5 plnts/pot. Thus, s th nsity of C. nnuum inrs, it inhiit th growth of its own popultion mor thn it inhiit th growth of A. livius popultion. Th sm ws tru for A. livius rprsnting lssi s of mutul ntgonism. Th rution of DW of ithr of C. nnuum or A. livius s its nsity inrs might u to th proution of lllohmils y C. nnuum (Rhoun & Rhim 214) n/or A. livius (Jl & Wongsrsin 212). Th DW lult for plnts of oth spis i not pn on thir mutul proportions (Fig. 5) Cp/pot Am/pot Totl/pot Dnsity of Amrnthus livius (numr of plnts pr pot) Fig. 1. Efft of nsity of Amrnthus livius grown in th pots with on Cpsium nnum plnt on th ry wight (DW) of C. nnuum n A. livius umult uring 4 ys, pr pot. Dt ws sprt y ANOVA, n signifint iffrns ssss y th F-tst n LSD t P =.5, n init y iffrnt lttrs ross nsitis. Brs rprsnt mns ± SE (n = 1) Unuthntit Downlo Dt 1/23/19 8:5 AM

6 Dry wight umultion of h spis in th mixtur pr pot (g) Dry wight umultion of Cpsium pr plnt n pot (g) Dry wight umultion of Cpsium n Amrnthus pr plnt (g) 84 A. Omzin, J.A. Tixir Silv Cp/plnt Am/plnt Totl/plnt Dnsity of Amrnthus livius (numr of plnts pr pot) Fig. 2. Efft of nsity of Amrnthus livius grown in th pots with on Cpsium nnuum plnt on th totl ry wight (TDW) of C. nnuum n A. livius umult uring 4 ys, on pr plnt sis. Dt ws sprt y ANOVA, n signifint iffrns ssss y th F-tst n LSD t P =.5, n init y iffrnt lttrs ross nsitis. Brs rprsnt mns ± SE (n = 1) DW/plnt DW/pot f Dnsity of Cpsium nnuum (numr of plnts pr pot) Fig. 3. Dry wight (DW) umultion of Cpsium nnuum uring 4 ys on pr plnt n on pr pot sis s fft y plnt nsity. Dt ws sprt y ANOVA, n signifint iffrns ssss y th F-tst n LSD t P =.5, n init y iffrnt lttrs ross nsitis. Brs rprsnt mns ± SE (n = 1) Cp/pot Am/pot Totl ry/pot f f Proportion of h spis in th mixtur Fig. 4. Dry wight (DW) umultion in Cpsium nnuum n Amrnthus livius plnts grown in th mixtur, xprss on pr-pot sis. n Cp = Cpsium, Am n = Amrnthus. Dt ws sprt y ANOVA, n signifint iffrns ssss y th F-tst n LSD t P =.5, n init y iffrnt lttrs ross proportions. Brs rprsnt mns ± SE (n = 1) f Unuthntit Downlo Dt 1/23/19 8:5 AM

7 Dry wight umultion of h spis in th mixtur in grm pr pot Comptition twn Cpsium nnuum n Amrnthus livius Cp/plnt Am/plnt DW/plnt f f Proportion of h spisin th mixtur Fig. 5. Dry wight (DW) umultion in Cpsium nnuum n Amrnthus livius plnts grown in th mixtur, xprss on pr-plnt sis. n Cp = Cpsium, Am n = Amrnthus. Dt ws sprt y ANOVA, n signifint iffrns ssss y th F-tst n LSD t P =.5, n init y iffrnt lttrs ross proportions. Brs rprsnt mns ± SE (n = 1) 2. Rltiv yils Th rltiv yils of C. nnuum (RY / pot n RY / plnt) n A. livius (RY / pot n RY / plnt) n th rltiv totl yil (RYT / pot n RYT / plnt) otin from th rplmnt sris r shown in Fig. 6 n 7. Ths prmtrs provi support for th omptitiv intrtion of h spis. Ths yil prmtrs wr signifintly fft y th mixtur rtios. Th rltiv yil (RY/pot) of C. nnuum inrs s its rtio rs from.46 t 5 C. nnum plnts to.85 t 1 C. nnuum plnt (Fig. 6). RY/pot rs from.79 to.37 whn th proportion of A. livius plnts in th mixtur inrs from 1 to 5 plnts/pot. Th RY of h spis ws < 1, initing tht thr ws mutul ntgonism twn oth spis. In this s, it is iffiult to trmin if th spis wr ntgonisti or whthr oth wr omptitivly using th sm rsours sin RYT osurs th hvior of h spis. Futur xprimnts tht xmin nutrint lvls in th soil n plnts t h rtio oul luit this mhnism. Th RYT (RY + RY) of th mixturs i not hng signifintly with h mixtur omintion (Fig. 6). This vlu grtr thn unit inits tht th two spis (C. nnuum n A. livius) us vill rsours mor ffiintly thn xpt s on thir rsptiv yils whn spis wr onsir iniviully. Vlus > 1 init tht whil two spis ompt for iffrnt rsours, thr is lso proly som gr of rsour omplmntrity twn thm (Ftn 213). Whn two ompting spis shr th sm rsour y oupying iffrnt rs or hitts, thn sptil rsour prtitioning ours (Yhi & Loru 27). Th oxistn of plnt spis my rsult from nih prtitioning, or from iffrns in rsour rquirmnts mong spis whil in th pross of omplmntrity, mor ivrs plnt ommunity n us rsours mor ompltly, n thus mor proutiv (Frily 21). Diffrns in plnt spis rihnss n fft osystm prosss through prtitioning of rsours, whry plnts in mor ivrs ommunitis my inrs totl rsour ptur, n thus inrs nt primry proution. Suh omplmntrity of rsour us my our in sp or tim, or pn on th typ of rsour (Ewl 1986). Spis tht r ply root hv mor ss to wtr n nutrints, whih r not vill to mor shllowly root spis (Johnson t l. 2). Th numr of C. nnuum roots rs with inrsing pth n istn from th stm (Gough 21). From nothr prsptiv, C. nnuum xplor uppr lyrs of th soil whil A. livius xplor pr lyrs (prsonl osrvtion). Thr ws omptitiv vntg of C. nnuum ovr A. livius whn th rtio of C. nnuum in rltion to A. livius ws ithr 5/1 or 4/2, rsulting in highr C. nnuum RY pr plnt (.79 n.36) n rs A. livius RY (. 9 n.13) (Fig. 7). Unuthntit Downlo Dt 1/23/19 8:5 AM

8 Rltiv yil of h spis (g ry wight pr pot) 86 A. Omzin, J.A. Tixir Silv This suggsts tht C. nnuum growth n ru th growth of A. livius whn its proportion is 5/1 or 4/2 whr th vlus r.85 n.35. For oth spis, RY is < 1, whih nots tht for oth spis intrspifi omptition ws grtr thn intrspifi omptition. In suh s, th iomss of ithr spis is ru in th prsn of th othr spis (Willims & MCrthy 21). Th rltiv totl yil (g TDW/pot) ws onstnt n grtr thn 1. Howvr, th RY for oth plnts ws not onstnt n ws < 1 (Fig. 6). RY follow th hypothtil lin xpt t th rtio 24, whr it vit from its hypothtil urv. RY ws lso < 1 ut ov th hypothtil lin. RY vit from th hypothtil lin for t lst two proportions (33, n 42). Ths rsults init, first, tht th two spis hv iffrnt mns for rsours, n son, tht A. livius ws mor omptitiv thn C. nnuum whn th nsity of C. nnuum ws grtr thn thr plnts lthough lss thn thr C. nnuum plnts pr pot m C. nnuum mor omptitiv thn A. livius. In suh s, thr ws nfit to A. livius n mg to C. nnuum. Son, th omptition twn oth plnts ourr for th sm nvironmntl rsours, whih wr us mor ffiintly y A. livius. A omprison twn C. nnuum n A. livius shows tht th rltiv yil of h plnt n rltiv totl yil of C. nnuum n A. livius in omptitiv rltionship wr ru s thir proportion in th mixtur hng, s vrifi y th onvity of th RY n RY urvs (Fig. 7). In ition, RYT ws < 1., whih inits ntgonist omptition ( Wit & Gourin 1978), whih suggsts intrfrn us y th lllopthi tion. Rhoun n Rhim (214) rport tht C. nnuum is toxi intr-spifilly n intr-spifilly ginst pr millt. Tsuhiy t l. (1994) stt tht th yils n qulity of C. nnuum in Kor h n rsing u to ontinuous ropping, suggsting tht lllopthy my hv ount for this phnomnon sin th wtr or orgni solvnt xtrts of lvs, stms, roots n soil in whih plnts h n ultivt inhiit s grmintion. Morovr, ths uthors rport tht th mthnoli xtrts of th stm n roots of C. nnuum strongly inhiit ril growth, whil th mthnoli xtrts of lvs n roots n quous root xtrt inhiit hypootyl growth of C. nnuum slings. This lllopthi potntil of iffrnt prts of th C. nnuum plnt my ppli to w mngmnt (Gonzlz t l. 1992, 1993). Cpsiin, unnt in th Cpsium gnus (C. nnuum, C. frutsns n C. hinns) (Al Othmn t l. 211), my t s n inhiiting lllohmil ftr ing rls into soil ftr th omposition of snsnt pppr tissus or y xution from thir roots n its fftivnss inrss s th os inrss, lthough th fftivnss iffrs mong trgt plnts (Kto-Noguhi & Tnk 23). 1,4 1,2 1,8,6,4,2 RY/pot RY/pot RYT/pot Proportion of h spis in th mixtur Fig. 6. Rltiv yils (RY) in g, ry wight pr pot of Cpsium nnuum (RY) n Amrnthus livius (RY) s wll s rltiv yil totl (RYT) stimt from Cpsium n Amrnthus grown in omptition in rplmnt xprimnt. = Cpsium, = Amrnthus. Dsh lins rfr to th rltiv hypothtil proutivity whn thr is no intrfrn y on spis with nothr. Dt ws sprt y ANOVA, n signifint iffrns ssss y th F-tst n LSD t P =.5, n init y iffrnt lttrs ross proportions. Brs rprsnt mns ± SE (n = 1) Unuthntit Downlo Dt 1/23/19 8:5 AM

9 Rltiv yil of h spis (g ry wight pr plnt) Comptition twn Cpsium nnuum n Amrnthus livius 87 1,2 1 RY/plnt RY/plnt RYT/plnt,8,6,4, Proportion of h spis in th mixtur Fig. 7. Rltiv yils (RY) in g, ry wight pr plnt of Cpsium nnuum (RY) n Amrnthus livius (RY) s wll s rltiv yil totl (RYT) stimt from Cpsium n Amrnthus grown in omptition in rplmnt xprimnt. = Cpsium, = Amrnthus. Dsh lins rfr to th rltiv hypothtil proutivity whn thr is no intrfrn y on spis with nothr. Dt ws sprt y ANOVA, n signifint iffrns ssss y th F-tst n LSD t P =.5, n init y iffrnt lttrs ross proportions. Brs rprsnt mns ± SE (n = 1) Tl 1. Vlus of rltiv rowing offiints (RCC) n ggrssivity for th mixtur of Cpsium nnuum n Amrnthus livius s fft y plnt nsity vlut ftr 4 ys ftr plnting Proportions of Cpsium : Amrnthus RCC of Cpsium nnuum RCC of Amrnthus livius Mns of ggrssivity 1/5 (16.6%) 5.1 ± ± ±.11 2/4 (33.3%) 2.65 ± ± ±.9 3/3 (5.%) 2.9 ± ±.51.7 ±.12 4/2 (66.6%) 1.24 ± ± ±.15 5/1 (83.3%) 1.38 ± ± ±.21 Mns ± SE in h olumn follow y sm lttrs t suprsripts r not signifintly iffrnt t p =.5 s on LSD tst. Exprimnt ws rpt twi. 3. Rltiv rowing offiint RCC (Tl 1) ws us to msur th omptitivnss of A. livius ginst C. nnuum n th omptitivnss of C. nnuum ginst A. livius. For C. nnuum, RCC rs from 5.1 to 1.24 s its proportion inrs from 1 Cp/5 Al to 4 Cp/2 Al, rsptivly. Th RCC of th proportion 5 Cp/1 Al ws slightly lrgr thn th proportion 4 Cp/1 Al. Howvr, th RCC of C. nnuum t two proportions (1 Cp/5 Al n 2 Cp/4 Al) ws grtr thn tht of A. livius. Th RCC of A. livius inrs from.82 to 2.95 s its proportion rs from 1 Cp/5 Al to 3 Cp/3 Al, rsptivly ut rs from 2.95 to 2.2 s its proportion rs from 3 Cp/3 Al to 5 Cp/1 Al, rsptivly. Howvr, th RCC of A. livius t thr proportions (3 Cp/3 Al, 4 Cp/2 Al n 5 Cp/1 Al) wr grtr thn tht of C. nnuum. Spis with highr RCC init tht it is mor omptitiv, or th strongr omptitor (Fishr t l. 21). Whn th proportions 1 Cp/5 Al, 4 Cp/2 Al, C. nnuum ws suprior omptitor thn A. livius. Howvr, t th proportions wr 3 Cp/3 Al, 2 Cp/4 Al, n 5 Cp/1 Al, A. livius ws suprior omptitor thn C. nnuum. A. livius h lowr RCC vlus thn C. nnuum whn its proportion ws lrgr thn 16.6%, initing tht A. livius ws lss ggrssiv towrs C. nnuum thn vi vrs (Tl 1). Aminpnh t l. (212) show tht th RCC vlus for ovgroun DW, root DW, tillr numr, lf r, n hight wr highr for two w spis (Ehinohlo rus-glli (L.) P. Buv. n Ehinohlo oryziol Vsingr) thn ultivt Oryz stiv L. Hshmi, initing tht oth w spis wr suprior omptitors to ri. 4. Aggrssivity Th ggrssivity of C. nnuum (Tl 1), whih is th iffrn twn th rltiv ry yils of Unuthntit Downlo Dt 1/23/19 8:5 AM

10 88 A. Omzin, J.A. Tixir Silv C. nnuum n A. livius, ws signifintly influn y th rtio of th spis omintion. Th inrs in th proportion of C. nnuum from 1 Cp/5 Al to 5 Cp/1 Al (16.6% to 83.3%) rs th ggrssivity of C. nnuum from to 5.71, rsptivly, Howvr, t th proportions of 1 Cp/5 Al n 2 Cp/4 Al (16.6% n 33.3%), ggrssivity ws positiv n t th proportions of 3 Cp/3 Al, 4 Cp/2 Al n 5 Cp/1 Al (5% to 83.3%), ggrssivity ws ngtiv. Th ggrssivity vlus for C. nnuum rs with its proportion in pot. It ws ominnt t 1 n 2 slings pr pot n not ominnt t highr proportions. Th ggrssivity of C. nnuum is moifi y its own prsn (utoggrssivity) s wll s y th prsn of A. livius. From ths rsults, inrsing proportion of C. nnuum in th mixtur rs its ggrssivity n inrs th ggrssivity of A. livius whil th highr rt of C. nnuum ru its ggrssivity. Whl t l. (29) show tht whn th ggrssivity vlu of on omponnt is positiv, thn tht omponnt is mor omptitiv thn th othr, n hs ominnt fft (Bhtti t l. 26). Our rsults support th finings of Srkr n Chkrorty (2), Srkr n Snyl (2) n Srkr n Kunu (21), who rport th ominnt fft of ssm (Ssmum inium L.) hving positiv ggrssivity vlu whn grown in ssoition with mungn (Vign rit L.), mshn (Vign mungo (L.) Hppr) n grounnut (Arhis hypog L.), rsptivly. Th ggrssivity of S. inium + A. hypog t 3 : 2 row rtio (Srkr n Chkrorty, 2), of S. inium + V. mungo t 2 : 1 row rtio (Srkr & Snyl 2), S. inium + V. rit t 3 : 2 row rtio (Srkr & Kunu 21) h positiv vlu of.37,.7 n.26, rsptivly. From our rsults, th ontrol of A. livius is highly rommn, in orr to prvnt its omptition, proly for nutrints, wtr, n light, thus ruing Cpsium growth. In this stuy, th fft of A. livius omptition my hv n ovrstimt u to pot siz. Pot siz proly ontriut to nutrint omptition u to onstrints in root growth us y smll soil volum. Mrkhm n Hlws (211) foun signifint rution in plnt growth whn soil volum ws ru. Morovr, plnts grown with nighors tn to smllr thn plnts grown lon (Lir & Arssn 25). Morovr, tking into ount tht intrfrn mong nighoring plnts ours ftr spifi plnt nsity hs n rh (Alrih 1987; Ronhi & Silv 26), in ition to omptition twn plnts, intr-spifi omptition mong iniviuls of th sm spis lmost rtinly h lso ourr, minly t highr nsitis. Unr fil onitions, soil volum rstrition to root growth is proly muh lowr thn tht osrv in pots, so fil trils woul rquir to tst this hypothsis n to s whthr th sm growth rsponss of oth rops woul rsult in th fil. Morovr, in Tunisi, A. livius nsitis in Cpsium fils r usully muh highr thn thos xmin in this stuy. Hhm (23) rport 45-5 slings of A. livius / 5 m 2 in th fil whr C. nnuum ws ultivt. This nsity oul l to highr gr of omptition rport in our stuy. CONCLUSIONS Th hrmful ffts of A. livius omptition on Cpsium plnt growth vri grtly pning on A. livius nsity. Ths vrs ffts of A. livius on Cpsium growth wr rought out proly through omptition minly for ssntil nutrints n light. Th inrs in th nsity of A. livius signifintly rs th growth of C. nnuum slings. Th rsults from th rplmnt sris init tht th omptitiv rltion twn C. nnuum n A. livius hng with th proportion of h spis in th mixtur. A. livius ws suprior omptitor thn C. nnuum t 33, 42 n 51. Th sm tnny ws osrv for C. nnuum, t 15 n 24, in whih C. nnuum ws suprior omptitor thn A. livius. Ths rsults suggst tht unr omptitiv onitions, C. nnuum prous mor thn xpt whn it is foun t lowr proportion in th mixtur thus intrspifi omptition is mor importnt thn intrspifi omptition. Th sm n si for A. livius, whih suffr from omptitiv intrfrn whn it ws mor unnt in th mixtur (i.., it suffr mor from intrspifi omptition thn from omptition with C. nnuum plnts). Howvr, singl ftor, suh s proportion, is not Unuthntit Downlo Dt 1/23/19 8:5 AM

11 Comptition twn Cpsium nnuum n Amrnthus livius 89 nough to prit intrfrn twn two spis. Futur stuis shoul vlut th fft of wtr, light n nutrints on th o-growth of ths spis. Unr th prsnt xprimntl onitions, whn vn on A. livius plnt ws l to signifintly rs th ry wight of C. nnuum slings, th ontrol of A. livius is highly rommn to prvnt omptition with C. nnuum n to inrs th growth (n onsquntly proutivity n yil) of C. nnuum. REFERENCES Agrwl A., Gupt S., Ahm Z. 27. Influn of plnt nsitis on proutivity of ll pppr (Cpsium nnuum L.) unr grnhous in high ltitu ol srt of Lkh. At Hortiultur 756: DOI: /AtHorti Alrih R.J Priting rop yil rutions from ws. W Thnology 1: Al Othmn Z.A., Ahm Y.B.H., Hil M.A., Ghfr A.A Dtrmintion of psiin n ihyropsiin in Cpsium fruit smpls using high prformn liqui hromtogrphy. Moluls 16: DOI: 1.339/moluls Aminpnh H., Shrifi P., Firouzi S Intrfrn intrtions of two spis of Ehinohlo gnus with ri. Chiln Journl of Agriulturl Rsrh 72: DOI: 1.467/S Aminpnh H Influn of nitrogn rt on omptition twn two ri (Oryz stiv L.) ultivrs n rnyrgrss (Ehinohlo rus-glli (L.) P. Buv). Intrntionl Journl of Biosins 3: DOI: /ij/ Asuzzmn M., Roni M., Ali M., Hsn M.M., Bgum M., Hsn M.M. t l Mothr ul wight n plnt nsity influn on s yil n yil ttriuts of onion. Intrntionl Journl of Vgtl Sin 21: DOI: 1.18/ Brry A.D., Stll W.M., Rthinspthi B., MDonl G.E., Chruttn R. 26. Aggrssivity: uumr vs. mrnth. W Thnology 2: DOI: /wt Bhtti I.H., Ahm R., Jr A., Nzir M.S., Mhmoo T. 26. Comptitiv hviour of omponnt rops in iffrnt ssm-lgum intrropping systms. Intrntionl Journl of Agriultur n Biology 8(2): Botright S.R., MKissik J.C Gorgi frm gt vlu rport. Ar Rport No Th Univrsity of Gorgi, Collg of Agriulturl n Environmntl Sin, Cntr for Agriusinss n Eonomi Dvlopmnt, 182 p. Boughll N., El Mhjou M. 25. Th fft of soil solriztion on Phytophtor niotin Br Hn vr. prsiti (Dstur) G.M. Wtrhous, rsponsl for synrom ssoiting root rots n mping-off of pppr (Cpsium nnuum L.) in Tunisi. Tropiultur 23: [in Frnh with English strt] Crvlho S.J.P., Buiss J.A.R., Nioli M., Lópz- Ovjro R.F., Christoffolti P.J. 26. Diffrntil susptiility of Amrnthus gnus w spis to th hriis trifloxysulfuron-soium n hlorimuron-thyl. Plnt Dninh 24: DOI: 1.159/S [in Portugus with English strt] Dkkr J Evolutionry ology of ws. W Biology Lortory, Dprtmnt of Agronomy, Iow Stt Univrsity, Ams, Iow, USA, 35 p. /EEWook.html (lst ss 6 April 216) Wit C.T., Gourin J Simultion of ologil prosss. Simultion Monogrphs. Cntr for Agriulturl Pulishing n Doumnttion (PU- DOC), Wgningn, Th Nthrlns, 175 p. Wit C.T On omptition. Vrslgn vn lnouwkunig onrzokingn 66:1-82. Ewl J.J Dsigning griulturl osystms for th humi tropis. Annul Rviw of Eology n Systmtis 17: DOI: /nnurv.s FAOSTAT 213. Pppr. (lst ss 6 April, 216) Ftn M Intr- n intr-spifi omptition twn slings of Ai ti n prnnil grss (Hyprrni hirt). Journl of Ari Environmnts 55: DOI: 1.116/S (3)52-1. Fishr A.J., Rmírz H.V., Gison K.D., Silvir Pinhiro B. 21. Comptitivnss of smiwrf upln ri ultivrs ginst plisgrss (Brhiri riznth) n signlgrss (B. umns). Agronomy Journl 93: DOI: /gronj x. Frily J.D. 21. Th influn of spis ivrsity on osystm proutivity: how, whr, n why? Oikos 93: DOI: 1.134/j x. Gonzlz L., Souto X.C., Bolno J.C., Rigos M.J Alllopthi potntil of iffrnt ssions of Cpsium nnuum L. pplition to w mngmnt. In: Proings of th 1992 Congrss of th Spnish W Sin Soity, pp Unuthntit Downlo Dt 1/23/19 8:5 AM

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