INFLUENCE OF EARLY BASAL LEAF REMOVAL ON YEALD COMPONENTS AND MUST QUALITY ON CV. SAUVIGNON BLANC

Abstract

The aim of this two-year trial was to investigate the effects of timing of basal leaf removal on yield components, grape structure and berry composition in cv. Sauvignon Blanc. The experimental vineyard belongs to Experimental Station “Radmilovac”, Faculty of Agriculture in Belgrade. The vineyard location is in a Belgrade wine region, characterized as a Cfb climate. Leaf removal treatments were manually applied at full bloom, at fruit set (3-5 mm berry diameter) and ten days before veraison. The treatments consisted of defoliation of the first six nodes of all the shoots. Berry development of all treatments followed a typical double sigmoid curve. This means that berries develop in two phases, separated by a phase of slow growth – lag phase. Defoliation performed during flowering and fruit set period reduced the number of berries per cluster and berry size, resulting in a reduction of yield per vine from 2.80 kg in control, to 1.64 and 1.78 kg in flowering and fruit set treatment, respectively. The influence of defoliation time on change in the skin to pulp ratio was determined in flowering and fruit set treatments. Defoliation treatments increased the content of soluble solids in must (24.5, 24.2 and 23.8%) in comparison with control (22.8%), while the content of total acids was not significantly changed. The early defoliation can significantly affect the structure of the cluster, yields and chemical composition of grapes, and from a practical perspective, can replace the costly and time-consuming cluster thinning as a tool of yield control.