TY - JOUR T1 - Crop Level and Harvest Date Impact Composition of Four Ontario Wine Grape Cultivars. I. Yield, Fruit, and Wine Composition JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. DO - 10.5344/ajev.2017.17019 SP - ajev.2017.17019 AU - Luis Hugo Moreno Luna AU - Andrew G. Reynolds AU - Frederick Di Profio Y1 - 2017/08/24 UR - http://www.ajevonline.org/content/early/2017/08/15/ajev.2017.17019.abstract N2 - Pinot gris, Riesling, Cabernet franc and Cabernet Sauvignon vines from a single vineyard in Virgil, Ontario were subjected to two crop levels [full crop (FC) and half crop (HC)], whereby crop was reduced in HC to one basal cluster per shoot at veraison. Crop level treatments were combined with three harvest dates: T0 (commercial harvest), T1 (three weeks after T0), T2 (six weeks after T0), all with subsequent wine production. Analysis of berries, must and wine were carried out. Reductions in crop led to an increase in Brix, reduced yield and cluster number in all cultivars, and an increase in cluster weight in Cabernet franc. Delayed harvest date also led to an increase in Brix and pH, and reductions in titratable acidity (TA) and berry weight. Effect of harvest date in berries carried through to musts and consecutively to wines; increases in pH and TA in T2 treatments were associated with reductions in anthocyanins, phenols and color intensity in red cultivars. It was concluded that delayed harvest date had a greater magnitude of effect than crop reduction, and therefore maintaining a full crop with a later harvest date might have a greater beneficial impact on potential wine quality than reducing crop level. ER -