Effect of Timing of Basal Leaf Removal on Yield Components and Grape Quality of Grapevine cvs Cabernet Sauvignon and Prokupac (Vitis vinifera L.)

Abstract

The examination of timing of partial defoliation was performed on cultivars Cabernet Sauvignon and Prokupac - Serbian autochtonous wine cultivar. Leaf removal treatments were manually applied at full bloom, at fruit set (3-5 mm berry diameter) and before veraison. The treatments consisted of defoliation of the first six nodes of all the shoots. Results indicate that defoliation carried out during the flowering and 3-5 mm berry diameter considerably influence the cluster structure and grape quality. Partial defoliation in these periods reduced the number of berries per cluster and berry size, resulting in a reduction of yield in both cultivars. Early defoliation increased dry matter content of the must. Defoliation treatments increased the content of total phenols in comparison with control, while the content of total anthocyanins was not significant changed in Canernet Sauvignon. In cv. Prokupac, early defoliation increased content of total phenols (in the full bloom and fruit set treatments) and total anthocyanins (in full bloom treatment). The increase in the content of total phenolics and anthocyanins occurred only in treatments applied at flowering and fruit set.