TY - JOUR T1 - Effects of Early Shading and Defoliation on Bunch Compactness, Yield Components, and Berry Composition of Aglianico Grapevines under Warm Climate Conditions JF - American Journal of Enology and Viticulture JO - Am. J. Enol. Vitic. DO - 10.5344/ajev.2014.14066 SP - ajev.2014.14066 AU - Boris Basile AU - Giulio Caccavello AU - Matteo Giaccone AU - Marcello Forlani Y1 - 2015/01/16 UR - http://www.ajevonline.org/content/early/2015/01/12/ajev.2014.14066.abstract N2 - Pre-bloom leaf removal is a canopy management practice used in viticulture to decrease bunch compactness at harvest. However, this practice may not be suitable in dry and warm viticultural areas, because it can result in excessive bunch exposure to direct sunlight and this can cause undesirable decreases in titratable acidity and increases in pH of berry juice. This study was designed to test the hypothesis that shading between pre-anthesis and fruit set can be an alternative strategy to decrease bunch compactness without removing leaves around the bunches. This may be beneficial to maintain berry juice acidity at harvest. The following eight treatments were compared: two defoliations (50% and 90%); five whole-canopy shadings (10%, 30%, 50%, 75%, and 90% reduction of ambient light), one partial-canopy shading (using a 30% shade net), and an unshaded and undefoliated control. Fruit set, berry number per bunch, bunch weight, and yield per vine were significantly affected by treatments. Bunch compactness was reduced by the 50% to 90% shading treatments. Surprisingly, defoliation decreased fruit set but not bunch compactness because of shortening of the total length of the bunch axes. Berry composition was not affected negatively by 50%-to-90% shading, whereas defoliations and 10%–30% shading caused a decrease in titratable acidity and an increase in pH of berry juice at harvest. Flower number per bunch in 2010 decreased linearly with decreasing net photosynthesis per shoot measured in 2009 between pre-bloom and fruit set. The results of this study suggest that early shading may be an efficient alternative practice to decrease bunch compactness without any negative effect on berry juice composition at harvest. ER -