Effects of Early Defoliation on Shoot Photosynthesis, Yield Components, and Grape Composition

• DOI: 10.5344/ajev.2006.57.4.397
• Publication Date: 2022-10-11T22:52:18Z
• Authors: Stefano Poni; Lorenzo Casalini; Fabio Bernizzoni; Silvia Civardi; Cesare Intrieri
• Keywords: Veraison; Thinning; Pruning

The effectiveness of early leaf removal on high-yielding cultivars Sangiovese and Trebbiano (<i>Vitis vinifera</i> L.) was investigated as a tool for reducing crop potential inducing looser clusters that are less susceptible to rot. Fruit set, cluster weight, berry number per cluster, size, compactness were reduced by all defoliation treatments compared non-defoliated shoots. Physiological assessment performed in one-year study indicated prebloom the six basal leaves elicited no difference between mean seasonal assimilation (A) shoot (2.91 μmol s⁻¹ control against 2.81 defoliated), fact due offsetting action more vigorous lateral formation higher A rates both main after veraison defoliated Grape composition improved (higher Brix anthocyanins phenolics Sangiovese) result assimilates being available unit cropping smaller berries characterized an increased skin-to-pulp ratio. three-year-study also showed carryover effects following year’s bud differentiation very few year x treatment interactions, suggesting prevailing over variability because climate. Overall, may be excellent yield control, replacing time-consuming manual thinning. time-consistent response suggests this practice improve grape composition.