CROP PRODUCTON HORTSCENCE 37(7): 1023-1027.2002. Performnce of Seyvl Blnc Grpe in Four Trining Systems Over Five Yers D. Ferree, T. Steiner, J. Gllnder, D. Scurlock, G. Johns, nd R. Riesen Deprtment of Horticulture nd Crop Science, Ohio Stte University, Wooster, OH 44691 Additionl index words. grpevine, wine, French-hybrid Abstrct. Own-rooted Seyvl Blnc vines were evluted over 5 yers in the following trining systems: bilterl cordon, bilterl cordon sylvos (sylvos), upright cordon-spur pruned, nd upright cordon-cne pruned. Vines in ll systems were spced 1.8 x 2.7 m nd were shoot thinned to 40 shoots nd cluster thinned to one cluster per shoot. Cumultive yields over 5 yers of the upright cordon systems were higher thn vines in the sylvos system. Averge weight of cne prunings ws higher in the upright cordon vines thn in ll other systems. Vines trined to the sylvos system hd more cnopy gps, less Botrytis bunch rot, nd higher juice soluble solids thn other systems in some yers. The chemicl constituents of the must nd wine or evlution by tsting showed little influence of trining system. Grpevine orienttion in spce through the trining system hs significnt effects, prticulrly on light distribution through the cnopy. These ltertions in microclimte ffect growth, yield, disese development, nd fruit composition. The French-Americn hybrid cultivr Seyvl Blnc cuses prticulr chllenges becuse of its tendency to overcrop resulting from production of fruiting shoots from noncount buds, nd lrge reltively compct clusters subject to bunch rot. A number of studies hve evluted trining systems for Seyvl Blnc with most emphsizing the need for cluster thinning nd comprison of vrious pruning severities (Morris et l., 1984; Reynolds et l., 1985, 1986: Reynolds nd Wrdle, 1994: Smithymn et l., 1997). Reynolds et l. (1986) recommended levels of 4 shoots/30 cm of row nd 17 clusters/500 g cne prunings to mximize yield nd mintin resonble fruit qulity nd vine size. Divided cnopy trining systems hve been shown to improve yields nd fruit qulity, prticulrly under conditions of excess vigor (Henry, 1992; Morris et l., 1984: Reynolds et l., 1996; Reynolds nd Wrdle, 1994; Shulis et l., 1966). n severl Europen countries, verticl cordon trining hs been used to divide cnopies using existing trellis configurtions. Kiefer et l. (1985) found verticl cordon-trined Riesling vines out-yielded other systems. The upright cordon system hs not been evluted on Seyvl Blnc nd my be dvntgeous if conventionl trellis system could be utilized to crete divided cnopy. Since pruning severity nd crop level hve been shown to hve lrge influences on Seyvl Blnc performnce, these were held constnt in our study. The objective of this study ws to determine the influence of four trining sys- tems on growth, yield, fruit composition, nd wine qulity of Seyvl Blnc. Mterils nd Methods n 1990, own-rooted Seyvl Blnc were plnted t spcing of 1.8 x 2.7 m in est- west rows on Bogrt lom soil t the Kingsville Bilterl Cordon Grpe Brnch of Ohio Stte Univ. locted djcent to Lke Erie. Soil mngement ws 1.O-m herbicide strip with mowed sod middles. During the first 2 yers, vines were trined to stke to chieve stright trunks nd in the third yer trined to the following systems: 1) bilterl cordon; 2) bilterl cordon sylvos (sylvos); 3) upright cordon-spur pruned; nd 4) upright cordon-cne pruned (Fig. 1). All systems were dormnt pruned nnully to leve totl of 40 count buds. Around bloom, shoot number ws djusted to 40 nd ech shoot ws cluster thinned to one cluster per shoot. n the bilterl cordon, the two cordons were fstened to the top wire (1.6 m). At pruning, three 5-bud cnes plus spurs totling 20 buds were left on ech side, nd fter cluster thinning the shoots werepositioned. n the sylvos, seven to nine-bud cnes were rched over wire t 1.2 m nd tied to lower wire (0.8 m). Ctch wires were used to verticlly trin the developing shoots. n July, shoots were tipped 30-40 cm bove the top wire (1.6 m). Upright cordons were trined with two equl cordons in the shpe of U with shoots developing in the bottom of the U (0.8 m) removed, thus, creting n open spce or diversion of the cnopy. n the spur-pruned version, 20 buds were left on ech side in two-to-three bud spurs nd in the cne pruned version, three 5- bud cnes were left on ech side plus spurs to equl 40 buds. The upright cordon systems received no shoot positioning or summer tip- Sylvos Received for publiction 28 Sept. 2001. Accepted for publiction 27 Feb. 2002. Slries nd reserch support provided by Stte nd Federl funds ppropritedtotheohio AgriculturlReserch&Development Ctr., Ohio Stte Univ. Mnuscript #HCS 01-11, Upright Cordon - Spur Upright Cordon - Cne Fig. 1. Digrms of orienttion fter dormnt pruning of four trining systems used for own-rooted Seyvl Blnc vines beginning in 1990. HORTSCENCE, VOL. 37(7), DECEMBER 2002 1023
CROP PRODUCTON ping. Whole rows of nine vines of ech trining system were rrnged s rndomized block with four replictions for totl of 36 vines for ech trining system. The following dt were nnully recorded: cluster number nd weight per vine, pruning time, nd weight of cne prunings. At hrvest, 100-berry smple ws tken from ech row, weighed nd pressed through fruit striner to collect the juice. Soluble solids were mesured using refrctometer (model 10480 SN; Abbe A 0 Scientific nstruments, Keene, N.H.). Mesurements of ph were tken using clibrted digitl ionlyzer (model 701A; Orion Reserch, Cmbridge, Mss.). TA ws determined by diluting 5 ml of juice into 100 ml of double-distilled wter nd titrting with stndrdized NOH solution until the solution reched ph of 8.2. Cnopy light interception ws mesured in 1996-98 erly in the seson just s growth strted, mid-seson nd just prior to hrvest on three vines in ech repliction. A white plstic sheet 1.8 x 2.7 m nd mrked on 15-cm squres ws plced on the soil surfce with the vine plced in the center. The sheet covered the soil re llotted to ech vine. On sunny dys, the number of mrks in shdow were counted t bout 1O:OO AM nd 2:OO PM nd used to clculte the percentge of light interception. A comprison of this method nd the use of ctul light sensors showed very high correltion (Wunsche et l., 1995). Cnopy density ws mesured nnully except for 1995 using the point qudrnt method using intersections every 15 cm t 1.O m nd 1.5 m bove the soil surfce (Smrt nd Robinson, 1990). Mesurements were mde on five vines in ech repliction voiding the end vines. Fruit distribution in the cnopy ws mesured by plcing frme with grid mrked in 25-cm squres nd counting the clusters in ech squre just prior to hrvest. The frme ws centered on the trunk nd three vines per repliction were mesured. mmeditely fter hrvest, the grpes were trnsported to the winemking fcilities t OARDC nd cooled overnight t 35 OF. The following dy they were destemmed nd crushed nd treted with potssium metbisulfite (50 mg.l-'). Biopectinse 300L (0.4 ml,l-' of 10% solution of Biopectinse in wter) ws dded nd the must settled overnight t 35 OF. The cler must ws rcked off, chptlized to 20 "Brix, supplemented with dimmonium phosphte (DAP) t 1 g.l-' nd inoculted with rehydrted dry wine yest t 0.25 g.l-'. Ech tretment ws fermented to dryness t 60 "F in triplictes in 20-L glss continers. At dryness, the wines were rcked into 12-L glss continers, treted with potssium metbisulfite (50 mg,l-') nd held t 35 "F for 3 months. The free SO, content ws djusted to 30 mg.l-' nd the wines bottled. Fifteen experienced judges were sked to rte the wines for rom, tste, nd overll qulity on numericl scle from 1-9, where 1 = excellent nd 9 = extremely poor. The wines (50-mL smples) were evluted t 1024 room temperture in three flights of four wines in glsses coded with rndomized 3- digit numbers. Ech flight consisted of one replicte of ech trining system. 12-10- 8-6- 4-0 Results Even with nnul cluster thinning, yields of 'Seyvl Blnc' were slightly influenced by trining system in three out of five yers (Fig. 2). There ws tendency for the upright cordon-cne pruned vines to hve higher yields nd sylvos trined vines to hve lower yields, but differences were not lwys significntly different. Cumultive yield of the upright cordon systems, both spur nd cne pruned, were significntly higher thn vines trined to the sylvos system (Tble 1). Averge pruning weight from upright cordon spur pruned vines ws higher thn for ll the other systems, which were similr to ech other. The pruning time required per vine ws highest for the bilterl cordon system nd lowest for the sylvos nd upright cordon-spur pruned vines. Although bunch rot levels were low most yers nd not influenced by trining systems, in 1997 bunch rot ws present nd vines trined in the sylvos system hd lower rot levels thn both of the upright cordon systems. A comprison of the verge chemicl components of the juice show no influ- 2-1 b b b ence of trining system on soluble solids concentrtion or titrtble cidity (Tble 1). However, ph of fruit from upright cordonspur pruned vines ws lower thn bilterl cordon fruit. A grid plced by the vine t hrvest showed tht the bilterl cordon concentrted the crop in the upper levels of the cnopy nd distributed it evenly from the trunk to the cnopy edge. The upright cordon systems hd n even distribution of the crop over the fruiting cnopy, while the crop on the sylvos vines were distributed lower in the cnopy nd hd less of the crop t the cnopy edge thn the other systems (dt not presented). An nlysis of the cnopy using the point qudrnt system shows tendency for fewer gps, more lef lyers nd greter percentge of interior leves for vines trined s n upright cordon-spur pruned vine (Fig. 3). n 1997, the yer sylvos vines hdlower mount of bunch rot, the cnopy of sylvos trined vines tended to hve more gps nd fewer interior leves. Vine light interception incresed s expected s the cnopy developed nd reched mximum round hrvest, intercepting 40% to 50% of vilble light (Tble 2). Mesurements erly in the seson indicte tht the bilterl cordon trined vines tended to intercept more light thn the sylvos, but differences - - UpCorC Fig. 2. Yield per vine of 'Seyvl Blnc' in the following four trining systems: Bilterl cordon (BiCor), Sylvos, Upright cordon-spur (Up Cor Sp). Upright cordon-cne (Up Cor C). Men seprtion by Duncn's multiple rnge test P 5 0.05. Tble 1.nfluence of four trining systems on cumultive yield nd verge cne pruning weight, pruning time, nd juice qulity components over 1994 through 1998. Avg Avg Pruning yieldvine cne pruning time 1997 Avg juice components Trining system (kg) wt/vine (kg) midvine %rot SSC ph TAg.L-' Bilterl Cordon 8.3 b' 0.58 b 2.11 9.3 b 18.9 3.16 10.2 Sylvos 7.6 b 0.54 b 1.78 b 3.0b 19.0 3.15 b 10.2 Upright cordon-spur 8.5 0.93 1.90b 12.5 19.1 3.13 b 10.3 Upright cordon-cne 8.7 0.72 b 1.85 b 10.3 19.1 3.14b 10.2 'Men seprtion by Duncn's multiple rnge test, P < 0.05 HORTSCENCE, VOL. 37(7), DECEMBER 2002
were not lwys significntly different from the other systems. At hrvest, sylvos trined vines tended to intercept less light nd the upright cordon vines the most light with interception in the other systems being similr or different from the extremes depending on the yer. v,. c3 8 The must nlysis is probbly the best reflection of the effect of trining system on juice chemicl components becuse it encompsses lrge smple. Soluble solids concentrtion in the must from the sylvos system were higher thn found in the upright cordonspur pruned vines in 1996 nd 1997 with the in. A E?, + -, - - B 94 96 97 94 96 97 60, i 40 94 96 T T 97 98 Yer Fig. 3. Cnopy composition significnt interction, between yer nd trining systems on Seyvl Blnc grpevines s mesured by the point qudrnt system: (A) percentge of gps,( B) lef lyers, (C) percentge of interior leves. Men seprtion by Duncn s multiple test, P 5 0.05. reverse occurring in 1995 (Tble 3). Must ph ws high from the bilterl cordon in 1996 nd 1998, but did not differ from one or more of the other trining systems. Although there were differences in titrtble cidity in two of the five yers, consistent influence of system ws not pprent. Although these trining systems displyed the cnopy in very different wys, the effect on must composition ws smll nd not consistent over the yers. Chemicl nlysis of the finished wine found no significnt difference in voltile cidity in ny yer (dt not presented). Wine ph ws ffected only in 1996 with wine produced from the upright cordon-cne pruned vines being higher thn from the sylvos system. A pnel of 15 winemkers evluted the wine from 1997 nd 1998 nd found tht in 1997, wine from the upright cordon-spur pruned vines hd better rom thn the wine from the sylvos nd upright cordon-cne pruned vines (Tble 5). Overll qulity of the upright cordon-spur pruned vines ws lso judged superior to the upright cordon-cne pruned vines. The judges found no effect of trining system on wine rom, tste or qulity in 1998. Discussion Since crop ws limited to one cluster per shoot nd vines in ll systems hd 40 shoots, it ws nticipted tht yield would be similr mong systems. There ws no difference in cluster weight or berry size in ny yer mong the systems. The slightly lower (10%) cumultive yields in the sylvos system ws likely relted to the lower cluster number per vine in 1996 nd 1997. Bending the cnes down hs been shown to reduce vegettive growth of grpes (Reynolds et i., 1985; Schubert et l., 1999) nd likely resulted in the reduced pruning weight, smller vine size nd lower yield of vines in the sylvos system. Since some cnes nd mny shoots were lso oriented downwrd (but not tied in this position) in the bilterl cordon, this my explin the lower pruning weight in this system compred to the upright cordon system. Trining the cordons upright nd pruning to two or three bud spurs incresed vegettive vigor nd resulted in higher pruning weight compred to other systems. Another concept tht is widely used s mesure of the blnce between vegettive growth nd cropping is crop lod (yield + pruning weight). A clcultion from the recommended optimum for Seyvl Blnc by Reynolds et l. (1986A) gives vlue of O-kg fruit per kilogrm of pruning weight. n the present study, the verged clculted crop lods were s follows: bilterl cordon 14.3, sylvos 14.0, upright cordon spur 9.1, nd upright cordon cne 12.0. Vlues recommended for V. vinifer cultivrs re generlly below O to mintin n optimum blnce between growth, yield, nd wine qulity (Brvdo et l., 1984). Ferree et l. (2002) reported n verge crop lod of 14 for Vidl Blnc nother French- Americn hybrid with vines pprently in blnce. This dt my suggest tht the optimumcrop lod for French- HORTSCENCE, VOL. 37(7), DECEMBER 2002 1025
CROP PRODUCTON Tble 2. nfluence of four trining systems on percentge of light interception of Seyvl Blnc vines over the seson using the dotlshde method. Light interception(%) time of seson Erly Mid Lte Trining system AM PM AM PM AM PM 1996 Bilterl Cordon 16 13 22 27 52 51 b Sylvos llb 10b 17 16c 42b 43b Uprightcordon-spur 12b 11 b 22 22 b 52 55 Upright cordon-cne 12 b O b 19 20b 51 53 1997 Bilterl cordon 17 9 35 32 44b 35b Sylvos 13b 14b 27b 26 42b 33b Upright cordon-spur 14 b 17 b 34 32 51 42 Uprightcordon-cne 13 b 15 b 32 29 50 42 1998 Bilterl cordon 6 6 30 25 49b 46 b Sylvos 5 5 24b 21 46 42 b Upright cordon-spur 6 5 22 b 22 55 52 Upright cordon-cne 6 5 24b 21 52 47b Men seprtion by Duncn s multiple test. P < 0.05. Americn hybrid grpes my be slightly higher thn for V. vinifer cultivrs. Yield of vines in ll systems ws prticulrly low in 1996 (Fig. 2). The low yield in 1996 lso occurred in commercil vineyrds nd hs been ttributed to rinfll bove the long- term verge in every month of the yer (Brown et l., 2001). Averge yield/h in this plnting over 5 yers rnged from 17.5 t.h- (7.0 t/cre) with the sylvos system to 20.5 t/ h (8.3 t/cre) in the cne pruned upright cordon. Except for 1996 when ll systems were below the threshold for productive French-Americn hybrids of 14.8 t.h-l(6.0 t/ cre) ll exceeded the threshold in other yers. Reynolds et l. (1986A) recommended 4 shoots/30 cm row nd 17 clusters/500 g cne prunings to mximize yield nd mintin resonble fruit qulity nd vine size of Seyvl Blnc. n this study, the vines exceeded tht recommendtion by 2 shoots/30 cm row nd 8 clusters/500 g cne prunings. Although these vines were cropped hevily, there ws no trend of reduced growth or yield over the 5-yer test period, nd in fct, the lrgest yield nd pruning weight occurred in the lst yer of the study. This consistent performnce ws likely relted to the nnul thinning of clusters tht hs been suggested s requirement for the successful mngement of Seyvl Blnc (Reynolds et l., 1986; Smithymn et l., 1997). Trining the vines in the sylvos system distributed the crop lower in the vine nd tended to result in cnopy with more gps, fewer lef lyers, nd fewer internl leves, lthough the differences were not lwys sttisticlly significnt (Fig. 3). n 1997 when significnt Botrytis bunch rot occurred, this more open cnopy resulted in less fruit infection. The smller nd more open cnopy of vines in the sylvos system ws confirmed by the tendency for lower light interception. Fruit from vines in this system hd higher soluble solids thn fruit from the most vigorous vines (upright cordon-spur pruned). Exposure of Seyvl Blnc clusters to light hs been shown to positively influence soluble solids (Hummel nd Ferree, 1998; Reynolds et l., 1986b). Dividing the cnopy in the upright cordon systems tended to improve yields compred to the sylvos system even with cluster thinning, which confirms reports of Kiefer et l. (1985) of incresed yields with this trining system. Other studies with other divided cnopy systems, prticulrly the Genev Double Curtin, hve lso improved yields of Seyvl Blnc, but require extensive trellis modifiction (Morris et l., 1984; Reynolds nd Wrdle, 1984). Vines trined to the upright cordon system mde more vegettive growth, tended to hve denser cnopy, prticulrly when spur pruned, nd intercepted more light. Lkso (1994) hs shown tht light interception is closely relted to yield with pple trees grown in wide rnge of trining systems. Severl uthors (Morris et l., 1984; Reynolds et l, 1985) hve suggested tht sustined yield of Seyvl Blnc is closely relted to growth mesured by cne pruning weight. The incresed vegettive growth of the upright cordon-spur pruned vines ws ssocited with improved wine rom nd overll qulity in one yer, but there ws no influence the following yer. Other studies (Reynolds et l., 1985, 1986) evluting the influence of trining systems on Seyvl Blnc wine qulity lso found only minor influences. All the trining systems in this study performed dequtely in comprison to the stndrd bilterl cordon system. The sylvos system reduced growth nd resulted in more open cnopy with less Botrytis bunch rot nd higher totl soluble solids. The upright cordon system tended to increse vegettive growth nd yield nd provides mens of dividing the cnopy using conventionl trellis. Literture Cited Brvdo, B. Y. Hpener, C. Loinger, S. Cohen, nd H. Titbcmn. 1984. Effect of crop level on growth, yield nd wine qulity of high yielding Crignne vineyrd. Amer. J. Enol. Viticult. 35(4):247-252. Brown, M.V., D.C. Ferree, D.M. Scurlock. nd G. Sigel. 2001. mpct of soil dringe on growth, productivity, cne diebck nd fruit composition of Chmbourcin nd Pinot Gris grpevines. HortTechnology 11:272-276. Ferree, D.C., G.A. Choon, D.M. Scurlock, nd M.V. Brown. 2002. Effect of time of cluster thinning grpevines. Smll Fruit Rev. (n Press.) Henry, S. 1992. Scott Henry trellis system. Oregon Wine Grpe Growers Guide 4h ed. 119-123. Hummell, A.K. nd D.C. Ferree. 1998. nterction Tble 3. nfluence of four trining systems on chemicl composition of Seyvl Blnc must over 5 yers (1994-98). Soluble solids concn (%) PH Titrtble cidity (g.l- ) Trining system 94 95 96 97 98 94 95 96 97 98 94 95 96 97 98 Bilterl cordon 17.5 18.7 b 18.0b 19.8 b 19.1 3.20 3.04 3.15 3.11 3.32 12.0 9.7 18.9 10.6 8.0b Sylvos 18.0 17.0~ 18.7 20.4 19.6 3.22 3.03 3.13b 3.09 3.22b 12.3 9.8 11.8b 10.3 8.1 Uprightcordon-spur 18.0 19.3 17.7 b 19.6b 19.8 3.20 3.04 3.10b 3.12 3.30 12.2 9.2 12.8 10.5 7.7 b upright cordon-cne 17.9 18.5 b 18.4b 19.8 b 19.5 3.20 3.02 3.12b 3.10 3.19 b 12.1 9.4 12.5 10.4 8.0b Men seprtion by Duncn s multiple rnge test P 5 0.05. Tble 4. nfluence of four trining systems on chemicl composition of Seyvl Blnc wine over 5 yers (1994-98). PH Titrtble cidity (g L-) Trining system 94 95 96 97 98 94 95 96 97 98 Bilterl cordon 3.12 3.10 3.29 P 3.25 3.45 8.8 7.6 b 11.1 11.1 7.6 Sylvos 3.08 2.97 3.2 lb 3.22 3.34 b 8.7 8.9 10.3 b 10.8 b 7.6 Upright cordon-spur 3.11 3.10 3.23 b 3.25 3.41 b 8.6 b 7.4 b 11.2 10.8 b 7.8 Upright cordon-cne 3.07 3.04 3.30 3.22 3.35 b 8.4 b 7.2 b 11.0 10.6 b 7.9 Men seprtion by Duncn s multiple rnge test P 5 0.05 1026 HORTSCENCE, VOL. 37(7), DECEMBER 2002
Tble 5. Summry of tste evlution of Seyvl Blnc wine s influenced by four trining systems. Arom Tste Overll ulitv, Trining system 1997 1998 1997 1998 1997 1998 Bilterl cordon 3.6 b 3.7 3.9 3.5 3.80b 3.6 Sylvos 3.76 4.3 4.2 3.9 4.0Ob 4.1 Upright cordon-spur 3.28 b 3.3 3.7 3.1 3.48 b 3.3 Upright cordon-cne 3.85 3.7 4.1 3.8 4.05 3.8 Averge of 15 independent judges using scle of 1 = excellent to 9 = extremely poor. >Men seprtion by Duncn s multiple rnge test P S 0.05. of crop level nd fruit cluster exposure on Seyvl Blnc fruit composition. J. Amer. SOC. Hort. Sci. 123(5):755-761. Kiefer, W., H.J. Eisenbrth, nd M. Weber. 1985. nitil results when testing the verticl trining system. Der Deutsche Weinbu, Wiesbden 40: 1122-1 125. Lkso, A.N. 1994. Apple. n: Hndbook of environmentl physiology of fruit crops. Vol. 1, p. 3-42. B. Schffer nd P.C. Anderson (eds.). CRC Press, Boc Rton, Fl. Morris, J.R., C.A. Sims, J.E. Bourgue, nd J.L. Okes. 1984. nfluenceoftrining system, pruning severity nd spur length on yield nd qulity of six French-Americn hybrid grpe cultivrs. Amer. J. Enol.Viticult. 35:23-27. Reynolds, A.G., R.M. Pool, nd L.R. Mttick. 1985. Effect of trining system on growth, yield, fruit composition nd wine qulity of Seyvl Blnc. Amer. J. Enol.Viticult. 36: 156-164. Reynolds, A.G., R.M. Pool nd L.R. Mttick. 1986A. Effect of shoot density nd crop control on growth, yield, fruit composition nd wine qulity of Seyvl Blnc grpes. J. Amer. SOC. Hort. Sci. 11 1:55-63. Reynolds, A.G., R.M. Pool, nd L.R. Mttick. 1986B. nfluence of cluster exposure on fruit composition nd wine qulity of Seyvl Blnc grpes. Vitis 25:85-95. Reynolds, A.G. nd D.A. Wrdle. 1994. mpct of trining system nd vine spcing on vine per- formnce nd berry composition of Seyvl Blnc. Amer. J. Enol. Viticult. 45(4):444-451. Reynolds, A.G.. D.A. Wrdle, A.P. Nylor. 1996. mpct of trining system, vine spcing, nd bsl lef removl on Riesling vine performnce, berry composition, cnopy microclimte, nd vineyrd lbor requirements. Amer. J. Enol. Viticult. 47(1):63-76. Schubert, A,, C. Lovisolo, nd E. Peterlunger. 1999. Shoot orienttion ffects vessel size. shoot hydrulic conductivity nd shoot orienttion rte in Viris vinifer L. Plnt, Cell nd Environ. 22: 197-204. Shulis, N., H. Amberg, nd D. Crowe. 1966. Response of Concord grpes to light, exposure nd Genev Double Curtin trining. Proc. Amer. SOC. Hort. Sci. 89:268-280. Smrt, R. nd M. Robinson. 1991. Sunlight into wine. Wine Titles. Underdle, South Austrli. Smithymn, R.P., G.S. Howell. nd D.P. Miller. 1997. nfluence of cnopy configurtion on vegettive development, yield nd fruit composition of Seyvl Blnc grpevines. Amer. J. Enol. Viticult. 48:482491. Wunsche, J.N., A.N. Lkso, nd T.L. Robinson. 1995. Comprison of four methods for estimting totl light interception by pple trees of vrying forms. HortScience 30:272-276. HORTSCENCE, VOL. 37(7), DECEMBER 2002 1027