Finl Progress Report Virgini Wine Bord, 20 July 2016 Optimized wine qulity potentil through fruit-zone mngement prctices in red vrieties Principl Investigtor: Tony K. Wolf AHS Jr. AREC 595 Lurel Grove Rd. Winchester VA 22602 (540) 869-2560 extn. 18 vitis@vt.edu Grdute Reserch Assistnt: Cin Hickey AHS Jr. AREC 595 Lurel Grove Rd., Winchester VA 22602 (540) 869-2560 extn. 27 cin1@vt.edu Type of Project: Reserch Amount funded: $37,957 Ojective: Evlute oth the severity nd the timing of fruit-zone lef nd lterl shoot removl for impcts on grpe rom precursors nd wine qulity potentil of two Bordeux red vrieties. Summry: The rtionle for fruit-zone lef removl in humid environment hs een driven more y disese mngement thn y documented chnges in fruit composition. Though common prctice for severl decdes, lef removl recommendtions remin generl nd re not vriety-, timing-, or mgnitude-specific. We evluted if the timing or mgnitude of fruit-zone lef nd lterl removl would lter fruit composition nd crop yield components of Cernet Suvignon, Cernet frnc nd Petit Verdot. Wine Bord funding requested nd provided during the 2015-2016 fiscl yer llowed us to finish this multi-yer project. Wge support ws principlly used to help conduct lortory nlyses nd dt interprettion of crotenoids in Cernet frnc nd Petit Verdot smples tht hd een collected nd frozen from ech of the 2012, 2013, nd 2014 experiments. Crotenoids re pigments tht perform photo-oxidtive protection in plnt systems, ut re lso precursors to some of the very importnt rom compounds, including norisoprenoids, in grpe vrieties. Funding lso provided grdute tuition nd stipend wrds for Fll, 2015 semester for grdute student Cin Hickey. Cin egn post-doctorl ppointment with Dr. Terry Btes t Cornell University in Ferury 2016, nd successfully defended his disserttion in My. This yer-end report principlly provides detils on wht ws done in the pst fiscl yer. In ddition, strcts of other spects of the multi-yer work re ttched s ppendices. Dr. Hickey is on tp to present his findings t the 2017 VVA Winter Technicl meeting (23-25 Ferury 2017), nd we re working on n Extension Bulletin tht trnsltes his reserch findings into grower recommendtions. Mjor findings nd pplictions of the multi-yer project include: - Removl of up to 6 leves per shoot post-fruit set incresed grpe phenolics nd nthocynins (oth y out 22%), which is positive outcome, nd reduced otrytis unch rot (76% compred with no lefing), without incresing risk of fruit sun-urning. - Pre-loom lef removl resulted in some of the sme trends in fruit qulity improvement; however, crop yields were reduced y the more ggressive pre-loom lef removl (8 leves per shoot) y nerly 60%. - The more modest pre-loom lef removl (4 leves/shoot) improved grpe composition without hving significnt effects on crop yield reductions.
- The more ggressive lef removl, whether conducted pre-loom or post-fruit set, tended to increse erry crotenoids in the pre-verison period. Certin crotenoids re precursors to rom compounds found in Cernet frnc nd Petit Verdot wines. - Removl of up to 4 leves/shoot pre-loom, or s mny s 6 leves/shoot post-fruit set, ppers to e n optiml cnopy fruit zone mngement strtegy to improve fruit composition, sustin n cceptle yield, nd reduce disese incidence with Cernet frnc nd Petit Verdot. - Our findings illustrte tht lef removl cn e more extensive, nd e performed erlier (preloom) thn trditionlly recommended, without risk of dversely impcting grpes. Bckground: Reserch dting ck to the mid-1980s hs shown tht exposing the fruit-zone of vine cnopies is eneficil, s fungl disese incidence is reduced nd fruit nd wine qulity re often improved. As such, fruit-zone lef removl ecme commonly recommended prctice, with more extensive lef removl often recommended. However, more recent reserch showed tht too much of good thing cn ctully e d, when extreme rdint heting of fruit ws shown to decrese grpe nthocynins in red vrieties. Some of tht reserch ws conducted in the rid conditions of centrl Wshington Stte nd the Centrl Vlley of Cliforni, where sky conditions were more conducive to sunurning of fruit. Therefter, fruit-zone lef removl ecme more conservtive, even in humid growing regions where shded fruit-zones excerte grpe fungl disese infections. Though conventionlly conducted fter fruit set, fruit-zone lef removl efore loom hs mny documented enefits, including improved juice solule solids, grpe phenolics nd nthocynins, nd reduced cluster compctness nd Botrytis unch rot incidence. We questioned whether erly (pre-loom) nd more extensive lef/lterl removl hd merit under the wrm/hot conditions of Virgini, nd on vrieties for which little or no fruit exposure reserch hd een conducted (C frnc nd P. Verdot). Our comprehensive ojective ws to evlute the effects of ggressive pre-loom nd post-fruit set lef removl on crop yield components nd fruit-composition in three regionlly importnt red Bordeux vrieties: Cernet frnc, Petit Verdot, nd Cernet Suvignon. Methods: Although presented in previous Wine Bord reports, the following provides some ckground on the nture of tretments used in the project. Project 1 ws conducted during the 2013-2014 sesons in commercil vineyrd in Shenndoh County. Two seprte experiments were conducted in djcent Cernet frnc nd Petit Verdot locks of the vineyrd. Cnopy tretments in oth vrieties included post-fruit set removl of fruit-zone leves to no (NO), medium (MED), or high (HIGH) levels of defolition, s well s pre-loom removl of fruit-zone leves to the high extent (P-B). Project 2 ws conducted for three sesons (2013-2015) with Cernet Suvignon grown t the AHS Jr. AREC vineyrd. Tretments were designed to evlute the effects of pre-loom nd post-fruit set lef removl on severl vine responses. The pre-loom lef removl experiment evluted no lef removl-control ( PB-NO ) nd pre-loom lef removl of four (PB-4) or eight (PB-8) sl leves nd lterls from primry shoots. A second experiment evluted no lef removl-control ( PFS-NO ) nd post-fruit set removl of six sl leves nd lterls ( PFS-6 ) from primry shoots. Additionl dt were only collected from Project 2 in 2015, nd consisted of mesurement of: fruit-zone rchitecture mesurement, erry temperture, erry weight over time, nd crop yield components nd primry juice chemistry t hrvest. Further, erry temperture ws logged on 1-minute intervls for the third consecutive seson. The mjority of l work in 2015 consisted of extrcting crotenoids from Petit Verdot nd Cernet frnc grpes, nd quntifying totl grpe nthocynins nd phenolics in ll three vrieties. Quntifiction of crotenoids with ultr-performnce liquid chromtogrphy-mss spectrometry (UPLC-MS) ws performed in the fll of 2015 nd into erly 2016 t the University of 2
Missouri s Grpe nd Wine Institute in Columi, MO. In ddition to completing the grpe crotenoid nd wine sensory dt nlysis, grpe temperture prediction model ws developed using erry temperture dt tht hd een collected over the 2013-2015 growing sesons (see Appendix C). Cnopy chrcteriztion nd dormnt cne pruning weight: Lef removl resulted in fruit-zone lef lyer numer (LLN) of zero in ll yers (Tle 1). Lef removl resulted in t lest three- nd, sometimes, four-fold increse in fruit-zone cluster exposure flux vilility (CEFA) compred to removing no leves, nd there ws no difference in CEFA etween PB-4 nd PB-8. Though differences etween PFS-6 nd PB-4 nd PB-8 could not e sttisticlly nlyzed, their LLN nd CEFA vlues were similr. As such, the pre-loom nd post-fruit set lef removl experiments offered pltform to compre the impct of lef removl timing without the confounding of fruit exposure extent. Lef lyer numer is commonly used index of cnopy density used y informed growers. CEFA is not common term in the grower s lexicon, ut it s widely used in viticulture reserch; it siclly defines the exposure of fruit clusters to the outside of the cnopy nd vlues rnge from complete occlusion/shding (~0.00) to complete exposure (~1.00). Pruning weight ws reduced y PB-8 in 2013 nd pruning weight tended to e further reduced over time when pre-loom lef removl ws re-implemented in consecutive sesons, ut only to significnt extent y PB-8 13re compred to PB-NO in 2014, nd oth PB-NO nd PB-4 in 2015. In other words, grower could expect to see reduction in vine cpcity if he or she chose to remove s mny s 8 leves per shoot from vines. Removing fewer leves did not hve this potentilly negtive impct on vine cpcity. Berry temperture: Berry temperture is n importnt consequence of cnopy mngement ecuse incresed erry temperture cn e desirle up to n extent (~30C), ut ove which undesirle responses, such s reductions in color density cn occur. Berry temperture ws incresed ove mient ir temperture from 0800-1200, nd from 3:00 to out 6:00 pm (Fig. 3 [note figure numers in this report re not sequentil]). This imodl trend of elevted erry temperture ws prlleled y imodl diurnl trend of elevted sunlight ( PAR ), prticulrly in the PB-4 nd PB-8 tretments (Fig. 3 A, B). The i-modl, dily pttern of fruit heting ws result of the VSP trining used; the overhed cnopy of folige locked the middy, rdint heting of the fruit. Est- nd westside erry tempertures were similr (-0.2 0.7 C) to mient ir temperture when no leves were removed (Figure 3C). Crop yield components nd vine fruitfulness: When compred to PB-NO in 2013, PB-8 generlly reduced components of crop yield to greter extent thn did PB-4. Crop yield, cluster weight, nd erry numer per cluster were reduced y PB-4 (30, 43, nd 44%, respectively) when compred to PB-NO (Tle 2). Crop yield, cluster weight, erry numer per cluster, nd erry weight were ll reduced y the most severe lef removl tretment, PB-8 (62, 62, 57, nd 9%, respectively) when compred to PB-NO, nd crop yield nd cluster weight were reduced y PB-8 (46 nd 33%, respectively) when compred to PB-4. Crop lod, which is the rtio of crop to pruning weight for given vine, ws reduced y oth PB-4 nd PB-8 when compred to PB-NO. Re-implementing the pre-loom lef removl tretments on the sme vines in 2014 nd 2015 tended to result in similr reduction in crop yield components s descried for the initil yer (2013) of tretment, wheres post-fruit set lef removl hd minor or no impct of crop yield components. Sesonl erry weight development: Berry weight tended to e reduced y PB-8 ut not y PB-4 or PFS- 6 (Fig. 8). In 2015, PB-8 reduced erry weight on ll dtes y n verge of 15% when compred to the verge erry weight of PB-NO nd PB-4 (Fig. 8 C). Berry weight ws reduced y PB-4 y 8% when compred to PB-NO only on 8 Septemer. Re-implementtion of pre-loom lef removl tretments in 3
the third consecutive seson (PB-4/8 13re) did not further reduce erry weight. Berry weight increse from 2 Aug to 8 Sep ws 0.15 g greter in PB-NO, nd 0.7 g greter in PB-4, when compred PB-8. Components of cluster compctness: Pre-loom lef removl of either 4 or 8 leves per shoot reduced cluster compctness in ech of the 3 yers evluted (Tle 3). This ws minly due to reduction in erries per cluster; however, the more severe lef removl tretment lso slightly reduced rchis length in 2013 nd 2015. The rchis is the stem of the cluster. There ws direct, positive reltionship etween reduction in erry numer per cluster nd cluster compctness, ut concomitnt reductions in rchis length confounded this reltionship. Grpe crotenoids: Our interest in the secondry metolites, crotenoids, stems from their role s precursors to certin rom compounds in grpes nd resultnt wines. For exmple, the norisoprenoid compound β-ionone, n importnt component of Cernet frnc nd Petit Verdot rom, is derived from oth lutein nd β-crotene. If the synthesis of crotenoids cn e enhnced, or their conversion to rom metolites incresed, improvements in wine qulity might e relized. Incresed grpe exposure through lef removl could e one mens of chieving tht outcome. The dt of tle 4 re one set of mny smples tht were nlyzed in 2015 for crotenoid concentrtion. These dt re for Cernet frnc tretments from the 2013 seson. Of the 4 crotenoids nlyzed, zexnthin nd lutein tended to e incresed y the more severe lef pulling in Cernet frnc (Tle 4). Similr trends were seen in other yers nd lso with Petit Verdot; however, β-crotene ws lso significnt incresed y lef removl in Petit Verdot. Wine sensory nlyses: Consumer preference tests of Cernet frnc nd Petit Verdot wines were conducted on the 2013 vintge in My 2015. Cernet frnc tretments included MED, HIGH, nd P-B, nd Petit Verdot tretments included NONE, MED, HIGH, nd P-B. Pnelists were weekly red wine consumers. A lnced complete lock design ws implemented, such tht ech prticipnt evluted wine smples from ll tretments. Smples were leled with rndom, three-digit codes, nd served mondiclly. Approx. 25-28 ml of ech wine ws served t room temperture in cler ISO wine glsses. Consumers clensed their pltes with unslted crckers nd filtered wter. Prticipnts nswered questions on 9-point hedonic scle (1 = dislike extremely, 9 = like extremely) (Perym nd Pilgrim 1957) for ppernce, red color, rom, overll flvor, stringency, mouthfeel, length of finish, nd overll impression. Additionlly, fruity rom nd flvor, vegettive rom nd flvor, nd intensity of red color, stringency, mouthfeel, nd length of finish were evluted on 5-point Just Aout Right (JAR) scle (1 = not nerly enough 3 = just out right; 5 = much too much). Pnelists performed sidey-side rnking of tretment wines t the end of the hedonic tests; the higher the verge rnking, the more preferred the wine. Dt were collected with SIMS softwre (Berkeley Heights, NJ). The intensity of red color nd stringency of P-B wines rnked higher on the just out right scle compred to MED wines in Cernet frnc (Tle 5). The intensity of red color of P-B nd HIGH wines rnked higher on the just out right scle compred to MED wines in Petit Verdot. Discussion: Removing leves efore loom consistently reduced crop yield wheres removing leves fter fruit set did not. Cluster weight ws the primry yield component reduced y pre-loom lef removl (likely due to reduced fruit set), nd it ws differentilly reduced y lef removl extent nd etween vrieties. For exmple, pre-loom lef removl of eight leves reduced erry numer per cluster nd cluster weight to greter extent thn pre-loom removl of four leves. Berry numer per cluster ws reduced to greter extent in Cernet frnc, nd erry weight nd cluster numer per vine were reduced to greter extent in Petit Verdot. We suggest tht these differences were due to the 4
direct reltionship etween lef re nd fruit set. Aggressive lef removl tended to reduce solule solids nd TA of hrvested fruit, ut these reductions were not consistent. Reduction in lef re ws likely responsile for reduction in solule solids, nd the sprser cnopy in Cernet frnc likely resulted in greter incidence of temperture-driven mlic cid respirtion compred to in Petit Verdot. Aggressive lef removl efore loom incresed totl grpe phenolics more consistently thn nthocynins cross ll three vrieties. This ppered to e prtilly, ut not exclusively, due to the concentrting effect of smller erries with this tretment. While lef removl never incresed totl grpe nthocynins in Petit Verdot or Cernet frnc, nthocynins were consistently incresed in Cernet Suvignon, suggestive tht temperture/rdition-induced increses in grpe nthocynins is vriety-dependent. Bunch rot incidence ws reduced to greter extent in pre-loom compred to post-fruit set lef removl plots, perhps due to looser clusters, etter erly-seson fruit-zone spry coverge, or oth. Fungl disese mngement nd totl grpe phenolics nd nthocynins cn e improved with ggressive lef removl in humid regions. While reduced TA cn result in less trt red wine, reduced solule solids is n unwelcome response in region tht often experiences dverse ripening period wether. The lor nd crop yield dets incurred with pre-loom lef removl my not e offset or even recovered y n incresed ottle price. Furthermore, repeted (over yers) pre-loom lef removl hs the potentil to reduce vine cpcity, mking the recovery from this prctice even longer. Thus, the potentil enefits need to e weighed ginst these potentil nd rel negtives. Impct sttement: The reserch hs quntified the impct of grpe cluster exposure on expression of rom precursors in three red Bordeux vrieties under the vrile climte growing conditions of Virgini. Findings hve reduced our concern for sun-urning of fruit (so long s vines re well hydrted), potentilly relizing greter enefits of exposure to disese mngement, nd wine qulity potentil enhncements. We hve not yet ssessed the impct of revised cnopy mngement recommendtions. Presenttions in this period: HICKEY C.*, T. Wolf. Mgnitude nd timing of fruit zone lef removl chnges yield nd fruit composition of Cernet Suvignon in humid region. Orl presenttion t 66th nnul meeting of the Americn Society for Enology nd Viticulture, Portlnd, OR., 15-18 June 2015. Tles, figures nd strcts: Detiled dt cn e found on in ppendices on pges 6-15 of this report. 5
Tle 1. Pre-loom nd post-fruit set lef/lterl removl effect on fruit-zone lef lyer numer (LLN) nd cluster exposure flux vilility (CEFA) mesured t verison, nd dormnt cne pruning weights, 2013-2015. 2013 2014 2015 Tretment LLN CEFA Prunin g weight (kg / m row) LLN CEFA Prunin g weight (kg / m row) LLN CEFA Prunin g weight (kg / m row) PB-NO 2.48 0.15 0.87 2.52 0.21 1.02 2.65 0.18 0.99 PB-4 0.04 0.54 0.91 0.02 0.75 0.99 0.05 0.82 0.94 PB-8 0.00 0.59 0.74 0.00 0.82 0.82 0.00 0.82 0.69 PB-4 13re n/ n/ n/ n/ n/ 0.90 n/ n/ 0.79 PB-8 13re n/ n/ n/ n/ n/ 0.66 n/ n/ 0.60 Significnce <0.000 <0.000 <0.000 <0.000 <0.000 <0.000 0.0002 0.0446 1 1 1 1 1 1 0.0086 PFS-NO n/ n/ n/ 2.73 0.19 0.99 2.66 0.14 1.31 PFS-6 n/ n/ n/ 0.00 0.77 1.02 0.00 0.77 1.18 Significnce n/ n/ n/ <0.000 <0.000 ns <0.000 <0.000 ns 1 2013: PB-NO, PB-4, PB-8 = pre-loom lef removl of no, four, nd eight leves, respectively; 2014: PB-4 13re, PB-8 13re = reimplementtion of PB-4 nd PB-8, respectively, on sme vines initilly used in 2013; 2015: PB-4, PB-8 = re-implementtion of PB-4 nd PB-8, respectively, on sme vines initilly used in 2014. PFS-NO nd PFS-6 = post-fruit set removl of no nd six leves, respectively. Significnce of tretment effects (p > F; ns = not significnt t 0.05 level). *Mens in sme tretment group (columns) not shring letter re significntly different t 0.05 level sed on djusted p- vlues using Tukey HSD (PB tretments) nd Student s T-test (PFS tretments). 1 1 1 6
30 25 A 800 700 600 Amient ir nd erry temperture, T ( C) 20 15 10 5 0 30 25 20 15 10 5 0 30 25 20 15 10 5 Berry T EAST Berry T WEST Amient T Amient PAR Fruit-zone PAR ~ solr noon 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 C B 500 400 300 200 100 0 800 700 600 500 400 300 200 100 0 800 700 600 500 400 300 200 100 Amient nd fruit-zone photosyntheticlly ctive rdition, PAR ( mol m -2 s -1 ) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Hour Fig. 3 Diurnl pttern of mient ir temperture, mient nd fruit-zone PAR, nd erry temperture s ffected y pre-loom removl of eight (A), four (B), nd no (C) fruit-zone leves/lterls. Dt logged on 15- nd 1-min intervls, nd verged over 2013-2015 sesons. Amient PAR ws logged on 15- nd 1-min intervls, nd verged over 2014-2015 sesons. NOTE: Amient PAR presented s 20% of ctul vlue to ese visuliztion of dt plots. 0 7
Tle 2. Pre-loom nd post-fruit set lef removl effects on crop yield components, crop lod, nd count nd sl shoot fruitfulness from 2013-2015. 2013 Tretment Crop yield Cluster Cluster Berry # (kg/ vine) numer weight (g) /cluster Berry weight (g) Crop lod Fruitfulness (count/sl) PB-NO 3.75 36 105.0 89 1.18 2.9 n/ PB-4 2.63 44 59.8 50 1.20 1.9 n/ PB-8 1.42 c 35 40.1 c 38 1.07 1.3 n/ Significnce c 0.0003 0.0011 <0.0001 <0.0001 0.0094 0.0013 n/ PB-NO 2.87 31 92.5 64 1.51 1.9 1.41 / 0.98 2014 PB-4 1.36 30 45.2 33 1.42 0.9 1.61 / 1.11 PB-8 0.90 27 32.3 26 1.30 0.7 1.35 / 1.01 Significnce c 0.0028 ns <0.0001 0.0003 0.0009 0.0124 ns / ns PB-NO-est. 3.39 26 139.3 98 1.51 2.3 n/ PB-4 13re 2.89 36 81.4 50 1.63 2.2 n/ PB-8 13re 1.71 31 56.6 c 40 c 1.43 1.7 n/ Significnce c 0.0204 ns <0.0001 <0.0001 ns ns n/ PFS-NO 3.37 26 149.7 104 1.47 2.2 n/ PFS-6 3.35 25 138.7 94 1.45 2.2 n/ Significnce c ns ns ns ns ns ns n/ PB-NO 4.76 39 121.2 83 1.47 3.2 1.66 / 0.33 PB-4 14re 2.25 c 39 57.3 42 1.37 1.7 1.52 / 0.36 PB-8 14re 1.00 d 37 26.5 c 22 c 1.17 1.0 1.35 / 0.19 PB-4 13re 2.38 43 55.4 40 1.39 2.1 1.53 / 0.33 PB-8 13re 1.09 cd 40 27.2 c 22 c 1.21 1.2 1.46 / 0.21 Significnce c <0.0001 ns <0.0001 <0.0001 <0.0001 0.0022 ns / ns PFS-NO 4.32 31 139.3 89 1.59 2.2 1.57 / 0.29 2015 PFS-6 3.99 31 129 89 1.46 2.3 1.57 / 0.25 Significnce c ns ns ns ns <0.0001 ns ns / ns 2013: PB-NO, PB-4, PB-8 = pre-loom lef removl of no, four, nd eight leves, respectively; 2014: PB-NO (est.) = estimted yield of PB-NO vines y dding ck hrvest weight of smpled erries throughout seson; PB-4 13re, PB-8 13re = reimplementtion of PB-4 nd PB-8, respectively, on sme vines initilly used in 2013; 2015: PB-4 14re, PB-8 14re = reimplementtion of PB-4 nd PB-8, respectively, on sme vines initilly used in 2014. PFS-NO, PFS-6 = post-fruit set removl of no nd six leves, respectively. Presented s cluster numer per shoot; count = one-yer old spur-originting shoot, sl = cordon-originting shoot. Fruitfulness ssessed in yer presented, ut effects ttriuted to previous seson s lef removl. 8
Tle 3. Pre-loom lef removl effect on components of cluster compctness from 2013-2015. 2013 Cluster Tretment Berry # / cluster Rchis length (cm) Compctness (erry # / cm rchis length) PB-NO 81 9.98 8.79 PB-4 53 9.68 6.55 PB-8 34 c 8.68 3.75 c Significnce c <0.0001 0.0179 <0.0001 2014 PB-NO 59 9.32 6.74 PB-4 34 cd 9.37 4.10 c PB-8 24 d 9.58 2.67 c PB-4 13re 53 9.39 6.27 PB-8 13re 41 c 7.91 5.92 Significnce c <0.0001 ns <0.0001 2015 PB-NO 80 10.09 9.03 PB-4 41 8.32 5.59 c PB-8 21 c 8.35 2.85 cd PB-4 13re 41 8.06 6.36 PB-8 13re 20 c 8.80 2.78 d Significnce c <0.0001 0.0069 <0.0001 2013: PB-NO, PB-4, PB-8 = pre-loom lef removl of no, four, nd eight leves, respectively; 2014: PB-4 13re, PB-8 13re = re-implementtion of PB-4 nd PB-8, respectively, on sme vines initilly used in 2013; 2015: PB-4, PB-8 = re-implementtion of PB-4 nd PB-8, respectively, on sme vines initilly used in 2014. PFS-NO nd PFS-6 = post-fruit set removl of no nd six leves, respectively. NOTE: Clusters smpled non-uniformly in 2014 six times totl in PB-NO/4/8 vines nd only t hrvest in PB-4/8 13revines. c Significnce of tretment effects (p > F; ns = not significnt t 0.05 level). *Mens in sme tretment group (columns) not shring letter re significntly different t 0.05 level sed on djusted p-vlues using Tukey HSD (PB tretments). 9
Tle 4. Pre-loom nd post-fruit set lef removl tretment effect on Cernet frnc grpe crotenoids in 2013. Lutein 5,6- Tretment epoxide (µg/g erry) Zexnthin (µg/g erry) Lutein (µg/g erry) β-crotene (µg/g erry) NO 0.015 0.019 1.21 0.73 MED 0.014 0.023 1.07 0.66 HIGH 0.018 0.039 1.29 0.75 P-B 0.016 0.042 1.34 0.75 Dte 14-Jul 0.020 0.028 1.57 0.76 26-Jul 0.015 0.040 1.56 0.88 14-Aug 0.012 c 0.025 1.48 0.88 30-Sep nd nd 0.30 0.37 Significnce c Tretment 0.001 <0.0001 0.004 ns Dte <0.0001 <0.0001 <0.0001 <0.0001 Tretment*Dte ns ns ns ns 10
Berry weight (g) 1.8 1.6 1.4 1.2 1.0 0.8 0.6 A B 0.4 0.2 1.8 9-Jul 24-Jul 9-Aug 30-Aug 9-Oct PB-8 PB-4 PB-NO 15-Jul 31-Jul 14-Aug 12-Sep 30-Sep 17-Oct PB-8 PB-4 PB-NO 1.6 C D Berry weight (g) 1.4 1.2 1.0 0.8 0.6 0.4 0.2 c c 30-Jun 16-Jul 2-Aug 8-Sep 5-Oct PB-8 PB-4 PB-NO PB-8 '13re PB-4 '13re 14-Aug 12-Sep 30-Sep 17-Oct PFS-6 PFS-NO Fig. 8 Pre-loom (A, B, C) nd post-fruit set (D) lef removl effect on erry weight over time in 2013 (A), 2014 (B, D), nd 2015 (C); Ech dt point is n verge of 120 erries; n = 6. Tretment men erry weight within dte not shring letter re significntly different ( 0.05) using Tukey's HSD. Error rs re +/- stndrd error. 11
Tle 5. Consumer preference of Cernet frnc nd Petit Verdot wines from the 2013 vintge. Cernet frnc Attriute d NO MED HIGH P-B Significnce e Appernce n/ 6.58 6.32 6.74 ns Red color n/ 6.71 6.87 6.89 ns Red color intensity n/ 3.15 3.31 3.45 0.0132 Arom n/ 6.37 6.50 6.51 ns Fruity rom n/ 3.32 3.14 3.25 ns Vegettive rom n/ 2.77 2.68 2.88 ns Fruity flvor n/ 3.36 3.27 3.29 ns Vegettive flvor n/ 2.81 2.93 2.99 ns Overll flvor n/ 6.15 6.35 6.39 ns Astringency n/ 6.04 6.18 6.27 ns Astringency intensity n/ 3.07 3.15 3.40 0.0474 Mouthfeel n/ 6.01 6.07 6.37 ns Mouthfeel intensity n/ 3.24 3.25 3.39 ns Length of finish n/ 6.06 6.26 6.19 ns Length of finish intensity n/ 3.20 3.20 3.30 ns Overll impression n/ 6.06 6.25 6.25 ns Side-y-side rnking n/ 2.07 2.00 1.93 ns Petit Verdot c Attriute d NO MED HIGH P-B Significnce e Appernce 7.36 7.31 7.33 7.21 ns Red color 7.33 7.21 7.31 7.33 ns Red color intensity 3.84 3.79 4.00 4.00 0.0495 Arom 6.49 6.52 6.64 6.44 ns Fruity rom 3.28 3.39 3.49 3.2 ns Vegettive rom 3.03 2.87 2.90 3.21 ns Fruity flvor 3.57 3.49 3.30 3.33 ns Vegettive flvor 3.16 2.97 3.18 3.13 ns Overll flvor 6.28 6.72 6.46 6.39 ns Astringency 6.31 6.64 6.36 6.44 ns Astringency intensity 3.36 3.20 3.23 3.34 ns Mouthfeel 6.28 6.30 6.31 6.25 ns Mouthfeel intensity 3.54 3.54 3.46 3.69 ns Length of finish 6.33 6.31 6.48 6.30 ns Length of finish intensity 3.41 3.36 3.21 3.52 ns Overll impression 6.23 6.44 6.33 6.26 ns Side-y-side rnking 2.37 2.33 2.73 2.57 ns NO = no lef removl; MED = post-fruit set removl of leves to medium extent; HIGH = post-fruit set removl of leves to high extent; P-B = pre-loom lef removl of six sl leves nd lterls. dthe following ttriutes rnked on scle of 1-9: ppernce, red color, rom, overll flvor, mouthfeel, length of finish, nd overll impression; the following ttriutes rnked on scle of 1-5: red color intensity, fruity nd vegettive rom, fruit nd vegettive flvor, stringency intensity, mouthfeel intensity, nd length of finish intensity; side-y-side rnking ws n verge of tretment rnking order, with 1 eing the fvorite. e Significnce of tretment effects (p > F; ns = not significnt t 0.05 level). *Mens in sme tretment group (rows) not shring letter re significntly different t 0.05 level. 12
Appendix A Extent nd timing of fruit-zone lef nd lterl shoot removl lters yield components nd fruit composition in Cernet Suvignon grpes. Bckground nd ims: Aggressive fruit-zone lef removl cn improve disese mngement, prticulrly in humid regions. However, current fruit-zone lef removl prctices tend to e conservtive nd hve seen little refinement over the lst decde or more. We hypothesized tht pre-loom removl of sl leves/lterl shoots would reduce crop yield nd tht ggressive sl lef/lterl shoot removl would improve totl phenolics nd nthocynins in Cernet Suvignon. Methods nd results: Two experiments were conducted to evlute the effects of pre-loom removl of no (PB-NO), four (PB-4), or eight (PB-8) sl leves/lterl shoots (Experiment 1, 2013-2015) nd postfruit set removl of no (PFS-NO) nd six (PFS-6) sl leves/lterl shoots (Experiment 2, 2014-2015) on crop yield components, nd totl grpe phenolics nd nthocynins in Cernet Suvignon. Experiment 1: Pre-loom removl of eight leves/lterl shoots reduced ll yield components to greter extent thn did PB-4. When compred to PB-NO, PB-4 reduced erry numer per cluster y 35-51%, cluster weight y 33-53%, nd crop yield y 51-53% over 2013-2015. When compred to PB-NO, PB-8 reduced erry weight y 9-19%, erry numer per cluster y 52-73%, cluster weight y 57-78%, nd crop yield y 55-78% over 2013-2015. When compred to PB-NO, yield components tended to e reduced y greter percentge due to re-implementtion of oth PB-4 nd PB-8 in consecutive sesons. Compred to PB-NO, PB-4 reduced cluster compctness y 25-39%, nd PB-8 reduced cluster compctness 58-68% over 2013-2015. Botrytis unch rot incidence ws reduced y PB-4 y 87% nd y PB-8 y 100% when compred to PB-NO in 2015. Pre-loom removl of eight leves/lterl shoots reduced solule solids in two of three yers, nd oth PB-4 nd PB-8 reduced titrtle cidity when compred to PB-NO in 2015. Both PB-4 nd PB-8 incresed totl grpe phenolics y n verge of 14-31% when compred to PB-NO over 2013-2015. While PB-4 incresed totl grpe nthocynins y n verge of 9% when compred to PB-NO in 2014, oth PB-4 nd PB-8 incresed totl grpe nthocynins y n verge of 22% when compred to PB-NO in 2015. Experiment 2: Botrytis unch rot incidence ws reduced y 78% y PFS-6. Post-fruit set removl of six leves/lterl shoots reduced solule solids in one yer, nd ph nd titrtle cidity in oth yers. Post-fruit set removl of six leves/lterl shoots incresed totl grpe phenolics in 2014 (13%) nd 2015 (16%), nd incresed totl grpe nthocynins in 2015 (13%). Conclusions: Aggressive removl of fruit-zone leves/lterl shoots tended to increse grpe phenolics nd nthocynins nd reduce otrytis unch rot incidence, regrdless of timing of removl. While preloom lef/lterl shoot removl resulted in greter concentrtions of these compounds in grpes compred to post-fruit set lef/lterl shoot removl, pre-loom lef/lterl shoot removl lso reduced crop yield y n verge of 57% compred to no lef removl. Significnce of the study: Aggressive removl of fruit-zone leves/lterl shoots improves the proility of getting disese-free fruit into the winery. Becuse the climte in humid growing regions is not s conducive to heting fruit to criticl tempertures s in other climtes, removing leves/lterl shoots to n equivlent of 0 fruit-zone lef lyers is not deleterious to fruit qulity. As such, disese mngement nd fruit qulity cn e concomitntly improved with ggressive lef removl. However, if removl of leves/lterl shoots occurs efore loom, crop yield cn e drmticlly reduced, depending on the extent of green tissue removl t this criticl stge. 13
Appendix B Extent nd timing of fruit-zone lef nd lterl removl lters yield components, grpe phenolics, nd crotenoids in Cernet frnc nd Petit Verdot. Bckground nd ims: The rtionle for fruit-zone lef removl in humid environment hs een driven more y disese mngement thn y documented chnges in fruit composition. Though common prctice for severl decdes, lef removl recommendtions remin generl nd re not vriety-, timing-, or mgnitude-specific. We evluted if the timing or mgnitude of fruit-zone lef nd lterl removl would lter fruit composition nd crop yield components of two regionlly populr red-fruited vrieties. Methods nd results: Two seprte experiments in djcent Cernet frnc nd Petit Verdot vineyrds evluted the effects of three post-fruit set lef/lterl shoot removl tretments [no removl (NO), removl from opposite the sl primry cluster nd the node directly ove (MED), nd removl from the node directly ove the distl primry cluster down to the cordon (HIGH)] nd one pre-loom (P-B) lef/lterl shoot removl tretment (removl from the six primry sl nodes). Post-fruit set lef removl hd mrginl, inconsistent effects on crop yield nd components. In Cernet frnc, P-B reduced crop yield y n verge of 50%, explined y reductions in cluster weight (39%), erry numer per cluster (33%), cluster numer (8%), nd erry weight (6%) compred to NO. In Petit Verdot, P-B reduced crop yield y n verge of 53%, explined y reductions in cluster weight (37%), cluster numer per vine (32%), erry weight (25%), nd erry numer per cluster (18%) compred to NO. Reimplementtion of P-B over two consecutive sesons cused further reduction in these yield components. Aggressive lef removl (HIGH nd P-B) tended to reduce solule solids in Petit Verdot ut not in Cernet frnc. HIGH tended to reduce titrtle cidity (TA) in oth vrieties, wheres P-B tended to reduce TA only in Cernet frnc. P-B more consistently incresed totl erry phenolics in Petit Verdot thn in Cernet frnc, ut lef removl did not increse totl erry nthocynins. When compred to NO nd MED, HIGH nd P-B tended to increse crotenoid ccumultion to greter extent in the pre-verison period, nd increse crotenoid degrdtion to greter extent in the postvérison period; this ws prticulrly consistent for zexnthin. The color nd rom of wines from different lef removl tretments were distinguished from one nother, leit infrequently. Color intensity ws rted higher in wines mde with fruit from P-B plots compred to wines mde with fruit from MED plots. Conclusions: Pre-loom lef removl reduced crop yield, nd differentilly ffected crop yield components etween vrieties. Pre-loom lef removl did not ffect grpe nthocynins nd inconsistently improved totl grpe phenolics. Lef removl of severl sl leves tended to increse crotenoid synthesis nd degrdtion compred to removing fewer leves, nd this ws more consistent in Petit Verdot compred to Cernet frnc. Lef removl hs potentil to increse the color intensity of young red wines nd chnge rom nd stringency, ut preference of these ttriutes ws not determined. Significnce of the study: Removing fewer leves efore loom, or more leves immeditely fter fruit set my e est fruit-zone mngement strtegies to modestly improve fruit composition, sustin n economicl crop yield, nd crete fruit-zone environment ssocited with reduced disese incidence in humid environment. 14
Appendix C Building n hourly grpe temperture-prediction model for verticlly-shoot positioned vineyrds in humid climte Bckground nd ims: Light nd temperture re importnt determinnts of rom nd flvor compounds in grpes nd, thus, wines. Metrics hve een developed, nd enhnced, tht chrcterize fruit-zone rdition, quntify the physicl nture nd sptil distriution of the fruit-zone, nd relte to fruit composition. However, few models re known to e ville tht cn ccurtely predict grpe temperture, even though it is ffected y oth fruit-zone rchitecture, nd mient ir temperture nd rdition. It ws sought to develop grpe temperture-prediction model to id in the meteorologicl risk ssessment of over-heting well-exposed grpes to known criticl temperture thresholds, such s those for nthocynins (30-35 C). Methods nd results: Amient nd fruit-zone photosynthetic ctive rdition (PAR), mient nd erry temperture, nd mient reltive humidity were logged over three consecutive growing sesons. Berry temperture extremes were ccounted for y logging the temperture of erries on the exterior fce of grpe clusters. The results were grower friendly models for ech 15 hour ngle tht predict erry temperture differentil from mient ir temperture from est nd west cnopy sides, in wellexposed nd shded fruit-zones, nd using mient rdition nd hour ngle. The difference etween mnully mesured nd predicted erry temperture rnged [0.17] to [2.84] C cross est nd west cnopy sides of differentilly lef-thinned fruit-zones, nd cross six different hour ngles rounded to the nerest 15. Conclusions: When fruit-zones re shded, erry temperture is highly predictle with mient ir temperture. The degree with which exposed erry temperture is heted ove mient ir temperture is dependent on severl fctors, including, ut not limited to, solr rdition, diurnl hour ngle, nd current mient ir temperture. The ility to predict erry temperture differentil from mient ir temperture ws complicted y fruit-zone lef removl prctice, cnopy side, hour ngle, nd mient rdition, prticulrly t diurnl periods of direct rdition penetrtion to the fruit-zone. Significnce of study: Hving the ility to predict erry temperture will permit growers to hve etter understnding of their site-specific risk of reching criticl grpe tempertures (i.e. for nthocynins). Growers cn ccordingly djust their fruit-zone mngement prctices. 15