Influence of early leaf removal on autochthonous and international grapevines in Sicily

Early leaf removal is an innovative viticultural practice for regulating yield components and improving grape quality. Direct sunlight interception by fruit has been associated with improved fruit quality and is generally desirable to some degree in most vineyards. The effects of early defoliation on four indigenous and international grapevines in Sicily were monitored. The experiment was conducted in a commercial Vitis vinifera L. vineyard located in the Ragusa district of Sicily over two consecutive years (2010 and 2011). The grapevines studied were Frappato, Nero d’Avola, Syrah and Cabernet Sauvignon grafted onto 140 Ru. rootstock. The treatments consisted of a control (no leaf removal) and of their removal from the cordon up to the leaf of the last cluster per shoot. Leaf removal at the earlier stages of cluster development appears to be an effective strategy in order to obtain smaller clusters and, therefore, control the vine crop load when coupled with other agronomic strategies.