WATER STRESS AFFECTS THE GERMINATION, EMERGENCE AND GROWTH OF DIFFERENT SORGHUM CULTIVARS

Size: px

Start display at page:

Download "WATER STRESS AFFECTS THE GERMINATION, EMERGENCE AND GROWTH OF DIFFERENT SORGHUM CULTIVARS"

Warren Wade
6 years ago
Views:

1 SINET: Ethiop. J. Si., 28(2): , 25 Fulty of Sin, is Univrsity, 25 ISSN: WTER STRESS FFECTS THE GERMINTION, EMERGENCE ND GROWTH OF DIFFERENT SORGHUM CULTIVRS Wonimu yu 1, N.F.G. Rthmn 2, P.S. Hmms 2, P.. Pitrs 2, J. Grimk 3 n M. Vn Dr Lin 3 1 Sirink griulturl Rsrh Cntr, PO ox 74, Wli, Wlo, Ethiopi E-mil: wonimuyu@yhoo.om 2 Dprtmnt of Plnt Proution n Soil Sin, Univrsity of Prtori, Prtori 2, South fri 3 Dprtmnt of Sttistis, Univrsity of Prtori, Prtori 2, South fri STRCT: Two xprimnts wr onut to stuy th ffts of wtr fiit strss on th grmintion, mrgn n sling growth of sorghum [Sorghum iolor (L.) Monh] using Compltly Rnomis lok Dsign in four rplitions. Fiv sorghum ultivrs (Jigurti, Gmll 117, Mko, 76 T1 #23 n P943) wr vlut unr thr wtr fiit strss trtmnts (, -.2 n -.85 MP) using PEG s n osmotium (Exprimnt Ι) n unr four vrying growing mi wtr ontnts (1, 6, 4 n 2% of fil pity) using sn (Exprimnt ΙΙ). In oth xprimnts, wtr fiit strss signifintly ru th rt n prntg of grmintion n mrgn n rly slings growth. Coloptil, msootyl, ril, n sling shoot n root lngths, s wll s root r wr vrsly fft y wtr fiit strss. Cultivrs iffr in th rt n prntg of grmintion, n mrgn n sling growth. Gmll 117, Mko n P943 h signifintly (P<.1) highr rts n prntgs of grmintion n mrgn. Th rt of grmintion n mrgn, th growth of th oloptil, msootyl, n ril n th shoot n root lngth n root r wr foun importnt trits to intify ultivrs tolrnt to wtr fiit strss t grmintion. Ky wors/phrss: Emrgn, grmintion, sling growth, sorghum, wtr fiit INTRODUCTION mjor onstrint of ryln sorghum proution, in th smi-ri rgions is th lk of suffiint wtr in th sing zon t plnting. Smi-ri rs, suh s thos of northstrn Ethiopi, r hrtriz y high tmprturs, high vportiv mns, n limit n rrti pripittion, rsulting in rpi rying of th soil surrouning th s thus ffting s grmintion, mrgn n thn sling s tlishmnt. Thus, wtr strss is n ovrriing nvironmntl ftor govrning grmintion n sling stlishmnt n onsquntly rop proution. Wtr fiit strss tolrn uring grmintion, mrgn n rly sling growth r prtiulrly importnt trits for sussful stlishmnt of rop plnts s ths trits trmin stn stlishmnt n fft th finl yil (rigg n ytnfisu, 1979). Dspit th ft tht grmintion n sling stlishmnt r importnt trits for th rly stlishmnt of plnts unr wtr fiit strss onitions, most stuis on wtr fiit strss tolrn hv fous on th lt vgttiv n rproutiv prio of growth. Nonthlss, trits of wtr fiit strss tolrn shoul lso inlu th ility of ss to grmint, mrg n stlish unr limit moistur vilility. oring to ly n kr (1996), grmintion, mrgn n sling growth unr wtr fiit strss onitions vry mong ultivrs of tf. Howvr, littl is known out th xtnt of gnti iffrns in grmintion, mrgn n sling growth mong iffrnt sorghum ultivrs grown in Ethiopi unr wtr fiit strss onitions. Thrfor, ths xprimnts wr onut to stuy th fft of wtr fiit strss on s grmintion, mrgn n sling growth of sorghum n to vlut ultivrs iffrns to intify ultivrs tolrnt to rought for furthr gronomi n ring importn. Exprimnt I MTERILS ND METHODS n xprimnt ws onut in th lortory of th Dprtmnt of Plnt Proution n Soil Sin of th Univrsity of Prtori. Fiv sorghum ultivrs (Jigurti, Gmll 117, Mko, 76 T1 #23 n P943) from Ethiopi, wr vlut for grmintion unr thr wtr fiit strss lvls,

2 12 rprsnting no strss ( MP), mil strss (-.2 MP) n svr strss (-.85 MP). Ths wtr fiit trtmnts wr s on th rsults from prliminry tril. Ss wr pl in ptri ishs, 9 m in imtr, lin with oul lyr Whtmn No. 3 filtr ppr isks. Th filtr pprs wr moistn with 7 ml of ithr pur wtr or polythyln glyol 6 (PEG-6) solutions of 1 or 2% (w/v). Th quivlnt wtr potntils wr, -.2 n -.85 MP, rsptivly. Ss wr grmint in n inutor mintin t onstnt tmprtur of 26 C in omplt rknss, for fiv ys. Th osmollity (C) of th PEG-6 solutions ws trmin with igitl Miro-osmomtr n onvrt from mosmol kg -1 to MP using Vnt Hoff s qution:? s(mp?) = RTSCj...(1) whr R is th gs onstnt (8.314 x 1-6 m 3 MP mol -1 K -1 ), T is tmprtur in Klvin ( C + 273) n Cj is Osmollity (onntrtion of prtils in on litr of wtr). Th ptri ishs wr hrmtilly sl with prfilm to prvnt vportion. Th xprimnt ws li out in ompltly rnomis lok sign with four rplitions. Th xprimntl lyout ws rrng in ftoril xprimnt with osmoti potntil n ultivrs s ftors. Grmintion ounts wr m vry 24 hours. Ss with ril protrusion of 2 mm or grtr wr onsir s grmint. ftr fiv ys th lngths of rils, oloptils n msootyls of 1 slings wr msur. Mn tim to finl grmintion (MTG) ws lult oring to rr n Stwrt (1994) from th formul: MTG () = S (n*)/n...(2) whr n is th numr of ss grmint twn soring intrvls; is th inution prio in ys t tht tim point n N is th totl numr of ss grmint in th trtmnt. vrg rts of grmintion (GR, % -1 ) wr lult oring to Emmrih n Hrgr (199) from th formul: GR (%, -1 ) = S [(Gi-Gi-1)/i]...(3) whr i is th grmintion ount y, Gi is th prntg of ss grmint through Dy i, n Gi-1 is th prntg of ss grmint through th prvious ount y. Exprimnt II Wonimu yu t l. Sling mrgn n growth of th fiv sorghum ultivrs (Jigurti, Gmll 117, Mko, 76 T1 #23 n P943) wr stui in pot xprimnt with four growing mi wtr ontnt lvls [fil pity (1% FC), 6% FC, 4% FC n 2% FC]. Fil pity is th wtr ontnt of th soil t whih ring rt is ngligil ftr sturtion. Th xprimnt ws onut s ftoril xprimnt with growing mi wtr ontnt lvls n ultivrs s ftors in ompltly rnomis lok sign with four rplitions. Wtr ontnt t fil pity of irri sn ws trmin y th grvimtri mtho. Th four soil wtr ontnt lvls (1%, 6%, 4% n 2% FC) wr hiv y ing 64, 38, 26 n 13 ml of wtr, rsptivly. Th wtr ws thoroughly mix with 2 kg of ir-ri sn using n ltri mixr. Th sn n wtr mixtur ws thn pl in polythyln gs in pots n lft for thr ys to quilirt. Th gs wr los to voi vportion. Fifty ss of h ultivr wr plnt in h pot. Th pots wr pl in growth hmr just to onstnt tmprtur of 25 C n omplt rknss until grminnt mrgn ws tt. Immitly ftr grminnt mrgn th growth hmr ws just to 12-hour photoprio. Slings wr grown in th growth hmr t 31 µ mol m -2 s -1 photosynthti rition. Grminnt mrgn ws ror for four ys strting from th first osrvtion of mrgn. Four ys ftr mrgn, ll ut ight uniform slings wr rmov from h pot. Elvn ys ftr mrgn, shoot lngth of ight slings ws msur n thn slings wr uproot n th totl root lngth n root r wr msur y snning th roots n nlysing th img with GSRoot nlysr. From mrgn t, th Emrgn Inx (I, % -1 ) ws lult using th formul of rr t l. (1992) whr: I (% -1 ) = S i/i... (4) whr i is th umultiv numr of slings mrg on y i, n i is numr of ys from plnting to y i. In oth xprimnts, t wr rnk prior to nlysis of vrin to mt th rquirmnts for NOV. nlysis of vrin for th msur prmtrs ws prform using th SS sttistil progrm (SS V8.2, SS Institut In., Cry, NC, US).

3 SINET: Ethiop. J. Si., 28(2), Exprimnt I RESULTS ND DISCUSSION Rt n prntg of grmintion Signifint (P<.1) iffrns in finl grmintion prntg wr osrv twn wtr fiit trtmnts n twn ultivrs. Th wtr fiit x ultivrs intrtions wr, howvr, non signifint. Th rsults of th min ffts of wtr fiit strss trtmnts init signifint (P<.1) rution in finl grmintion prntg unr svr wtr fiit strss (-.85 MP) (8.3%), whil grmintion prntg unr mil wtr fiit (-.2 MP) (95.6%) ws omprl to th ontrol ( MP) (94.7%) (Fig. 1). Th rution in grmintion prntg is u to low s wtr uptk. Rution in wtr uptk impirs ll turgor n thn ll ivision n longtion thry inhiiting ril protrusion (Gurmu n Nylor, 1991). oring to Grnr t l. (1985) lss-thn-optimum growing mi wtr ontnt usully rsults in prtil imiition, whih oftn rsults to low ll turgor. Prntg grmintion, vrg ross wtr fiit strss trtmnts, iffr twn ultivrs whr Gmll 117, Mko n P943 h th highst grmintion prntgs, whil 76 T1 #23 h th lowst grmintion prntg (Fig. 1) MP -.2 MP -.85 MP Prnt FGP GR Prnt FGP GR Jigurti Gmll 117 Mko 76 T1 #23 P943 Figs 1 n. Efft of wtr fiit strss () n ultivr iffrns () on finl grmintion prntg (FGP) n vrg grmintion rt (GR). Mns follow y th sm lttrs for h prmtr r not signifintly iffrnt t P.5.

4 122 Wonimu yu t l. Th rt of grmintion (% -1 ) iffr signifintly only mong th min ffts of wtr fiit trtmnts n mong ultivrs. Th rsults init n inrs rution in th rt of grmintion s th wtr fiit strss lvl inrs (Fig. 1). Th rt of grmintion ws ru y 23% unr mil wtr fiit strss (-.2 MP) n y nrly 5% unr svr wtr fiit strss (-.85 MP) onitions. Unlik grmintion prntg, th rt of grmintion ws signifintly fft y mil wtr fiit strss (-.2 MP) initing tht th rt of grmintion is mor snsitiv to mil wtr strss thn grmintion prntg. This rsult is in grmnt with tht of Fllri (1994) who osrv grtr fft of wtr fiit strss on th rt of grmintion thn on grmintion prntg. Th rsults of ultivr iffrns in th rt of grmintion init tht Gmll 117, Mko n P943 h signifintly (P<.1) highr rts of grmintion ompr to Jigurti n 76 T1 #23 (Fig. 1). Th rt of grmintion rng from 58.2% -1 for Gmll 117 to 39.9% -1 for 76 T1 #23. Rpi grmintion prmits th sonry root systm to ss wt soil h of th rying front in smi-ri nvironmnts (lki t l., 1999). Signifint (P<.1) iffrns in mn grmintion tim (MGT) wr osrv mong th wtr fiit strss trtmnts n mong ultivrs. vrg ross ultivrs, MGT inrs s th wtr fiit strss lvl inrs (Fig. 2). Lfon n kr (1986) lso osrv n inrs in grmintion tim in wht s osmoti strss ws inrs. Sorghum ultivrs iffr in MGT with Gmll 117, Mko n P943 rquiring shortr tim whil Jigurti n 76 T1 #23 rquiring longr tim to rh finl grmintion (Fig. 2). Th prntg n rt of grmintion of rop ss r of onsirl gronomi importn. Rution in th rt of grmintion u to wtr fiit woul prtiulrly ritil in smi-ri rs whr moistur vilility in th s zon ours for rif prio. Thus, on of th most importnt gronomi spts of rop stlishmnt is th rt t whih suffiint numr of ss grmint n stlish stn uring th limit prio whn nvironmntl onitions r suitl. Coloptil, msootyl n ril lngth Signifint (P<.1) iffrns in oloptil lngth wr osrv twn wtr fiit strss trtmnts n twn ultivrs. Th wtr fiit x ultivrs intrtions wr not signifint. vrg ross ultivrs, oloptil lngth progrssivly rs with inrsing wtr fiit strss (Fig. 3). Th lngth of th oloptil ws ru y 34% unr mil wtr fiit strss (-2 MP) n y 77% unr svr wtr fiit strss (-.85 MP) onitions, ompr to th ontrol ( MP). Rution in oloptil lngth unr wtr fiit strss is in orn with th rsults of Lfon n kr (1986) in wht. Th vlopmnt of wk oloptils unr wtr fiit strss implis poor opportunity for slings mrgn n stlishmnt. Dys Dys Jigurti MP -.2 MP -.85 MP Gmll 117 Wtr fiit strss lvls Mko Cultivrs 76 T1 #23 Figs 2 n. Efft of wtr fiit strss () n ultivr iffrns () on mn tim to finl grmintion. rs follow y th sm lttrs r not signifintly iffrnt t P.5. P943

5 SINET: Ethiop. J. Si., 28(2), Coloptil lngth iffrns twn ultivrs wr signifint with Gmll 117 hving th longst oloptil. Th othr four ultivrs h omprl oloptil lngths (Fig. 3). Th osrv vriility in sorghum ultivrs with rspt to oloptil lngth is in grmnt with th rsults of Wnjri n hoyr (198). Coloptil lngth (mm) Coloptil lngth (mm)` Jigurti Gmll 117 Mko Cultivrs 76 T1#23 P943 Figs 3 n. Efft of wtr fiit strss () n ultivr iffrns () on oloptil lngth. rs follow y th sm lttrs r not signifintly iffrnt t P.5. Msootyl lngth iffrns twn th intrtion ffts of wtr fiit strss n ultivrs wr signifint (Fig. 4). In ll ultivrs, msootyl lngth rs s wtr fiit strss inrs, ut th xtnt of th rs iffr for h ultivr, with Gmll 117 n P943 MP -.2 MP -.85 MP Wtr fiit strss lvls hving th lst rutions (27 7% n 13 67% rsptivly). Msootyl lngth rs from mm t MP to 8 2 n 2 6 mm t -.2 n -.85 MP, rsptivly. This osrvtion grs with th rports of Tkhshi (1978) who osrv inhiit msootyl n oloptil growth in ri unr wtr fiit strss. Cultivrs Gmll 117 n P943, hving longr oloptils n msootyls unr wtr fiit strss, oul hv ttr potntil for rpi mrgn from th soil s sorghum slings mrg from th soil y longting th msootyl n oloptil. Coloptil n msootyl longtion prmtrs r importnt trits in vluting s grmintion unr wtr strss s rt n prntg of grmintion lon nnot ssur sling mrgn (Tkhshi, 1978). Thus, ultivr sltion for wtr fiit strss tolrn uring th grmintion stg shoul inlu oloptil n msootyl longtion prmtrs. Signifint iffrns in ril lngth wr osrv twn th intrtion ffts of wtr fiit strss n ultivrs (Fig. 4). Ril lngth in Jigurti, Gmll 117 n 76 T1 #23 rs progrssivly s th lvl of wtr fiit strss inrs. Whrs in Mko n P943 ril lngth rs signifintly only unr svr wtr fiit strss (-.85 MP). Unr mil (-.2 MP) n svr (-.85 MP) wtr fiit strss onitions, ril lngth rs y 17 to 52% for Jigurti, 16 to 46% for Gmll 117, 3 to 47% for Mko, 18 to 63% for 76 T1 #23 n 6 to 47% for P943 rltiv to th ontrol ( MP). Unr mil wtr fiit onition only 76 T1 #23 iffr signifintly from th rst of th ultivrs. ut unr svr wtr fiit strss, mor ultivr iffrns wr osrv whr 76 T1 #23 n Gmll 117 vlop signifintly shortr n longr rils rsptivly. oring to Gurmu n Nylor (1991), inhiition of ril mrgn n growth unr wtr fiit strss oul u to impirmnt of ll ivision n longtion rsulting from rution in th turgor of th ril lls. Gurmu n Nylor (1991) rport similr rsults whr ril longtion in sorghum n wht ws rtr unr low wtr potntil.

6 124 Wonimu yu t l MP -.2 MP -.85 MP Msootyl lngth (mm)` fg fg g fg f Jigurti Gmll 117 Mko 76 T1 #23 P943 Cultivrs 12 MP -.2 MP -.85 MP Ril lngth (mm)`` f f f f 2 Jigurti Gmll 117 Mko 76 T1 #23 P943 Cultivrs Figs 4 n. Efft of wtr fiit strss on th msootyl () n ril () lngths of sorghum ultivrs. rs follow y th sm lttrs r not signifintly iffrnt t P.5. Exprimnt II Rt n prntg of sling mrgn Signifint (P<.1) iffrns in prntg sling mrgn wr osrv twn th wtr ontnt x ultivr intrtion ffts. No plnts mrg in th 2% FC trtmnt n this trtmnt is xlu from th isussion. Th rsults init tht for ll ultivrs, xpt Jigurti n P943, mrgn strt lining t 4% FC, whil in Jigurti n P943 it strt lining t 6% FC (Fig. 5). t 6% FC Gmll 117, Mko n P943 n t 4% FC Gmll 117 n P943 rgistr signifintly highr prntg mrgn thn Jigurti n 76 T1 #23. Th ttr mrgn in Gmll 117 n P943 in this xprimnt grs with th osrvtion in

7 SINET: Ethiop. J. Si., 28(2), Exprimnt I whr ths two ultivrs vlop longr oloptils n msootyls. Compr to mrgn t fil pity (1% FC), Jigurti (21 n 34%) n 76 T1 #23 (6 n 35%) h th highst rution in mrgn t 6 n 4% FC. Gmll 117 (3 n 8%) n P943 (6 n 15%) wr th lst fft. oring to rr t l. (1992), th rution in sling mrgn t low growing mi wtr ontnt possily rsult from low s-wtr ontt. This is pprntly us th wtr is sor on th surf of th soil prtils with for grtr thn th soring pity of th s. Furthrmor, t low wtr ontnts th rt of soil moistur movmnt is too slow to supply suffiint wtr to th immit nvironmnt of th s for its grmintion (Huntr n Erikson, 1952). Emrgn inx (% y -1 ), prmtr initing th rt of mrgn, rs following th rs in growing mi wtr ontnt (Fig. 5). Gmll 117, Mko n P943 h th highst n Jigurti n 76 T1#23 th lowst rts of mrgn t ll growing mi wtr ontnt trtmnts. Ths ultivrs h similr prformn in th PEG xprimnt for th rt of grmintion. Emrgn (%) ' f f 1% FC 6% FC 4% FC f f 2 Jigurti Gmll 117 Mko 76 T1 #23 P943 Cultivrs Emrgn inx (% y -1 )`` % FC 6% FC 4% FC Jigurti Gmll 117 Mko 76 T1 #23 P943 Cultivrs Figs 5 n. Efft of growing mi wtr ontnt on finl sling mrgn () n mrgn inx (). rs follow y th sm lttrs r not signifintly iffrnt t P.5.

8 126 Wonimu yu t l. Sling shoot n root lngth n root r Sling shoot lngth ws signifintly (P<.1) fft y th intrtion ffts of growing mi wtr ontnt n ultivrs (Fig. 6). In ll th ultivrs, shoot lngth ws signifintly (P<.1) ru with rsing growing mi wtr ontnt. Shoot lngth ws ru y 14 n 27% for Jigurti, 24 n 38% for Gmll 117, 19 n 42% for Mko, 18 n 35% for 76 T1 #23 n 21 n 4% for P943 t 6 n 4% FC, rsptivly. Root lngth ws signifintly (P<.1) iffrnt twn th growing mi wtr ontnt n ultivrs intrtion ffts (Fig. 7). Th t init tht rution in growing mi wtr ontnt h vrsly fft th root lngth of ll ultivrs, xpt in 76 T1 #23 (Fig. 7). Root lngth rs y 41 n 51% for Jigurti, 34 n 41% for Gmll 117, 3 n 36% for Mko n 33 n 49% for P943 unr 6 n 4% FC, rsptivly. Unr no strss onition (1% FC), Jigurti prou signifintly longr roots, whil th rmining ultivrs h omprl root lngths. t lowr growing mi wtr ontnt (6 n 4% FC) oth Jigurti n 76 T1 #23 vlop signifintly longr roots ompr to th othr ultivrs. Root lngth in 76 T1 #23 ws vn promot y inrsing wtr fiit strss, whih is proly n ptiv rtion. Gwronsk n Grzlk (1993) rport similr osrvtion in tritil, whr root growth unr wtr strss ws inrs ompr to wll wtr plnts. oring to M Rgw t l. (1995), ultivrs tht n stlish long xtnsiv sling root systms my hv ttr sling stlishmnt s thir root systms r l to rpily pntrt th uppr soil lyrs n ontinu wtr uptk, thus voiing wtr fiit strss. Thus, sltion for vigorous n p pntrting root systm on th sis of root lngth oul n sy mtho of slting for rought rsistn. Th rsults init tht Jigurti n 76 T1 #23 oul hv ttr sling stlishmnt t lowr growing mi wtr ontnt s thy n vlop ttr root systms. 18 1% FC 6% FC 4% FC Shoot lngth (m)`` f f 4 2 Jigurti Gmll 117 Mko 76 T1 #23 P943 Cultivrs Fig. 6. Efft of growing mi wtr ontnt on shoot lngth. rs follow y th sm lttrs r not signifintly iffrnt t P.5.

9 SINET: Ethiop. J. Si., 28(2), Diffrns in root r wr osrv twn th intrtion ffts of growing mi wtr ontnt n ultivrs. In ll ultivrs, xpt in 76 T1 #23, root r lin signifintly (P<.1) s growing mi wtr ontnt rss. Whil in 76 T1 #23 root r inrs with rsing lvls of growing mi wtr ontnt (Fig. 7). Rltiv to th rsptiv wll wtr plnts, root r unr 6 n 4% FC ws ru y 37 n 5% in Jigurti, y 33 n 48% in Gmll 117, y 32 n 57% in Mko n y 25 n 53% in P943, rsptivly. Totl root lngth (mm/sling)`` % FC 6% FC 4% FC Jigurti Gmll 117 Mko 76 T1 #23 P943 Cultivrs Root r (Sq. mm/sling)`` % FC 6% FC 4% FC f fg gh fgh hi i hi Jigurti Gmll 117 Mko 76 T1 #23 P943 Cultivrs Figs 7 n. Efft of growing mi wtr ontnt on totl root lngth () n r () of sorghum ultivrs. rs follow y th sm lttrs r not signifintly iffrnt t P.5.

10 128 Wonimu yu t l. CONCLUSION In oth xprimnts inrsing wtr fiit strss ru th rt n prntg of grmintion n mrgn, s wll s th rly growth of slings s init y oloptils, msootyls n ril longtion n sling shoot n root lngth n root r. Th sp of grmintion n mrgn, th growth of th oloptil, msootyl, n ril n th shoot n root lngth n root r wr foun importnt trits to intify ultivrs tolrnt to wtr fiit strss t grmintion. Th prsn of ultivr iffrns in wtr fiit tolrn t grmintion ws monstrt in ths stuis. Gmll 117, Mko, n P943 wr foun to tolrnt to wtr fiit strss s thy h signifintly highr rt n prntg of grmintion n mrgn. Thy rquir lss tim to rh finl grmintion. Morovr, Gmll 117 vlop signifintly longr oloptils, msootyls n rils, whih r importnt ttriuts for ttr mrgn unr wtr fiit strss. In trms of shoot lngth n root systm vlopmnt, Jigurti n Mko prform ttr. Jigurti n 76 T1 #23 vlop longr root systm with lrgr root r, whih r importnt ttriuts for rly stlishmnt unr wtr strss onition. Rsults of ths stuis suggst tht thr is potntil to slt for wtr fiit strss tolrn within th Ethiopin sorghum gn pool. Thus, th rsults r vry usful for rrs for futur vlopmnt of rought tolrnt ultivrs n for gronomists to prit sowing rts pning upon xpt soil moistur onitions. REFERENCES 1. lki, R.Z., Zuryk, R.., lik, M.M. n Tlhouk, N.S. (1999). Grmintion n sling vlopmnt of rought tolrnt n susptil wht unr moistur strss. S Si. Thnol. 27: ly, S. n kr, D.. (1996). n vlution of rought srning thniqus for Ergrostis tf. Trop. Si. 36: rr, G.S. n Stwrt,.. (1994). Grmintion unr ontroll tmprtur n fil mrgn of 13 sorghum ultivrs. Crop Si. 34: rr, G.S., Stinr, J.L., Ungr, P.W. n Prihr, S.S. (1992). Moling sorghum sling stlishmnt from soil wtnss n tmprtur of rying s zons. gron. J. 84: rigg, K.G. n ytnfisu,. (1979). Th fft of sing rt, sing t n lotion on grin yil, mturity, protin prntg n protin yil of som spring wht in ntrl lrt. Cn. J. Plnt Si. 59: Emmrih, W.E. n Hrgr, S.P. (199). Polythyln glyol solution ontt ffts on s grmintion. gron. J. 82: Fllri, E. (1994). Efft of wtr strss on grmintion in six provnns of Pinus pinstr it. S Si. Thnol. 22: Grnr, F.P., Pr, R.. n Mithll, R.L. (1985). Physiology of rop plnts. Iow Stt Univrsity prss, US. 9. Gwronsk, H. n Grzlk, K. (1993). S grmintion n sling vigour of tritil (X Tritiosl wittmk) unr rought strss. Plnt vr. ss 6: Gurmu, M. n Nylor, R.E.L. (1991). Efft of low wtr vilility on grmintion of two sorghum ultivrs. S Si. Thnol. 19: Huntr, J.R. n Erikson,.E. (1952). Rltion of s grmintion to soil moistur tnsion. gron. J. 44: Lfon, G.P. n kr, R.J. (1986). Effts of tmprtur, moistur strss, n s siz on grmintion of nin spring wht ultivrs. Crop Si. 26: M Rgw, L.R.F., Wtson, J.R. n Gourly, L.M. (1995). Sltion rspons for sling root lngth n oloptil lngth in prl millt. Crop Si. 5: Tkhshi, N. (1978). ptiv importn of msootyl n oloptil growth in ri unr iffrnt moistur rgims. ust. J. Plnt Physiol. 5: Wnjri, K.. n hoyr, M.P. (198). Coloptil lngth in sorghum. S Si. Thnol. 8:

TURFGRASS DISEASE RESEARCH REPORT J. M. Vargas, Jr. and R. Detweiler Department of Botany and Plant Pathology Michigan State University

I TURFGRASS DISEASE RESEARCH REPORT 9 J. M. Vrgs, Jr. n R. Dtwilr Dprtmnt f Btny n Plnt Pthlgy Mihign Stt Univrsity. Snw Ml Th 9 snw ml fungii vlutin trils wr nut t th Byn Highln Rsrt, Hrr Springs, Mihign