TY - JOUR T1 - Evaluation of the Concord Crop Load Response for Current Commercial Production in New York JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. DO - 10.5344/ajev.2020.20026 SP - ajev.2020.20026 AU - Terry Bates AU - Rhiann Jakubowski AU - James A. Taylor Y1 - 2020/08/20 UR - http://www.ajevonline.org/content/early/2020/08/17/ajev.2020.20026.abstract N2 - Economic pressures in the NY Concord grape industry over the past 30 years have driven crop management practices toward less severe pruning to achieve larger crops. The purpose of this study was to investigate the effect of crop load on juice soluble solids and the seasonal change in vine pruning weight in NY Concord grapevines. Over a four-year period, vines were balanced pruned at two levels or fixed node pruned at two levels to give four pruning severities. For balanced pruning, vines were pruned to leave 33 or 66 fruiting nodes for the first 500 g pruning weight and an additional 11 nodes for each additional 500 g pruning weight. For fixed node pruning, vines were pruned to 100 or 120 fruiting nodes per vine. The 120 node vines were also manually cluster thinned at 30 days after bloom to target 0, 25, or 50% crop removal. In a second study, the 120 node pruning with mid-season fruit thinning was repeated over 11 years to assess seasonal differences on the crop load response. Crop load was measured as the yield to pruning weight ratio (Y:PW) and ranged from 1 to 40 in this study. On average, the industry standard of 16 Brix was achieved at a Y:PW of 20 and no seasonal pruning weight change was observed at Y:PW of 17.5. There was a positive linear relationship between seasonal GDD and the Y:PW needed to reach 16 Brix as well as between seasonal precipitation and the Y:PW required to observe no seasonal pruning weight change. The results from this study were used to improve crop load management recommendations for NY Concord vineyards under current practices. ER -