Evaluation of the impact of vine pruning periods on grape production and composition: an integrated approach considering different years and cultivars

Several studies have already highlighted how late pruning, conducted after bud break, can result in a delay in phenology and, consequently, in ripening. However, the effects of pruning periods on vegetative and productive parameters are less well-known. This study aimed to evaluate the effect of pruning periods on ripening kinetics, grape composition at harvest and yield parameters, considering the grapevine cultivar and year. The experimentation was conducted from 2011 to 2013 in two of the main Italian wine-growing areas: Franciacorta, in Northern Italy, and Montefalco, in Central Italy. In Franciacorta: Chardonnay and Pinot noir were considered while in Montefalco, the varieties included were Sauvignon blanc, Grechetto di Orvieto, Sagrantino, and Sangiovese. Six different pruning periods were compared: at leaf fall (NOV), during dormancy (DEC, JAN, FEB), in the pre-bud break period (MAR), and late, post-bud break (APR). Results obtained showed that the effects of the pruning period are clear and sufficiently replicable only considering pre-bud break pruning (MAR). The observation of the ripening kinetics highlighted in fact a delay in grape ripening for APR in both contexts as well as a lower value for the sugar-acidity ratio at harvest. In terms of grape yield, a moderately negative effect of APR was observed in Montefalco, while a more severe effect was observed in Franciacorta. This analysis gives a comprehensive understanding of the effects of pruning timing on grape yield and composition, providing viticulturists with transversally applicable information, useful for an aware management of the vineyard.