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52 WINES&VINES June 2016 GRAPEGROWING PRACTICAL WINERY & VINEYARD F. After two days, the grapes were manually destemmed while frozen. Berries from different clusters were pooled and sealed in storage bags for each field-replicate respectively and stored at -80° C until analysis of secondary metabolites. Results and discussion Weather and vine performance Weather conditions: Weather data varied between years and the two trial sites. Focus was placed on seasonal weather comparisons of the Alpine vineyard, as the trial was replicated at that site for two years. The 2011 season was cooler than 2012, with mean daily tem- peratures being 0.36° F cooler in 2011 and heat unit accumulation 63 GDD 50 lower than in 2012. Precipitation in the 2011 growing season was more than double that of 2012. Consistent with the different weather condi- tions, vine phenological develop- ment exhibited temporal variation between years and sites. The number of days between bud break and harvest was nearly two weeks longer at the Dayton site (2010) than at the Alpine site in 2011 and 2012. At the Alpine site, warmer temperatures and less precipitation in 2012 led to ad- vanced fruit ripening and an ear- lier harvest compared to 2011. In 2012, fruit reached about 25° Brix at 39 days post-véraison, while fruit reached about 20° Brix at 45 days post-véraison in 2011. (See table "Basic Fruit Maturity at Har- vest Relative to Leaf Removal" on page 51.) Vines were delayed in develop- ment in 2011 due to a cool spring and summer, and fruit was not allowed to remain on the vine as long to achieve higher TSS. Vine growth: No differences were found in the number of shoots and clusters per vine, yield or clus- ter weight relative to leaf-removal treatments within each year. This is to be expected, as vines were man- aged to typical commercial stan- dards with standardized number of buds per vine at pruning, and shoot and cluster thinning practices re- sulted in uniform shoot and cluster counts in the vineyard. Leaf-removal treatments effec- tively resulted in different amounts of leaves removed from the cluster zone. In 2010, the 100% leaf re- moval had 641 cm 2 more leaf area per vine removed than the 50% leaf removal treatment (p = 0.0181), for a total of seven more leaves removed per vine. More basal leaves were removed in the 100% treatment than the 50% and IS treatments in 2011 (p<0.0001) and 2012 (p=0.0004). The 100% leaf-removal treatment removed 25% to 27% of leaves per vine when treatments were applied in 2011 and 2012, respectively. The 50% and IS treatments had similar leaf area removed (15% to 16%) in 2011 and 2012. Despite differences in the amount of leaves removed, whole- vine leaf area did not differ by treatment when measured at vé- raison in 2010 or 2011. This is likely because the amount of leaves removed at the pea-size stage is only a small fraction of the total leaf area present on the vine at véraison, since grapevine cano- pies continue to grow in shoot length and lateral shoot develop- ment until véraison. 58 Similarly, S. Poni et al. found no differences in total leaf area later in the season, with leaf removal con- ducted pre-bloom because of in- creased lateral leaf shoot growth. 37 There was a minor difference in vine leaf area at véraison in 2012, with 100% and IS treatments hav- ing 23% and 9% less leaf area, re- spectively, than the control (None). C. Intrieri et al. found differences in total shoot leaf area with leaf re- moval in Sangiovese, but results were due to differences in lateral leaf area, not main shoot leaf area. 17 The 2012 lateral shoot number differed by treatment (p = 0.0129), with the 100% treatment having fewer lateral shoots and the small- est total leaf area. It is possible that the differences in leaf area between 2011 and 2012 were due to the differences in precipitation from bloom to véraison, with 0.3 inches in 2012 compared to 5.7 inches in 2011. Basal leaf removal treatments in this study did not remove enough leaves to compromise vine function, as yield, pruning weights CLUSTER ZONE SUNLIGHT EXPOSURE 70 60 50 40 30 20 10 0 % Ambient PAR 100% 50% IS None 100% 50% IS None 100% 50% IS None 2012 Percent of ambient photosynthetically active radiation received in the cluster zone at 10 a.m., solar noon and 2:30 p.m. in 2010, 2011 and 2012. Treatments include all cluster zone leaves removed (100%), half of all cluster zone leaves removed (50%), industry standard with east-side only leaves removed (IS), and no leaves removed from the cluster zone (None). Different letters above error bars indicates a difference in means between treatments using Tukey HSD mean separation at √=0.05. 70 60 50 40 30 20 10 0 2011 70 60 50 40 30 20 10 0 2010 10 a.m. Solar noon 2:30 p.m. a a ab bc c b b b a b ab c a b b a b ab