EFFECT OF LEAF AREA ON THE GRAPE COMPOSITION AND SENSORY QUALITY OF WINES FROM CULTIVAR MERLOT (Vitis vinifera L.) IN SAO JOAQUIM, SC, BRAZIL

The management of the canopy is designed to improve the distribution of shoots and leaves to encourage the uptake of solar radiation, decrease the shading within the canopy and prevent the formation of microclimate favorable to disease development. The balance between leaf area and yield benefits plant growth and grape composition. These studies are still scarce in the wine regions of Brazil. The aim of this study was to evaluate the effect of management leaf area on the grape composition and sensory quality of Merlot wines produced in Sao Joaquim, SC. Plants were evaluated in a commercial vineyard, established in 2002, conducted in vertical trellis system, at an altitude of 1,293m, during cycles 2005/2006 and 2006/2007. The treatments of leaf area were made from the topping of the shoots, keeping 12, 16, 20 and leaves without topping of shoots, with the removal of all lateral shoots. The control treatment received no manipulation of the canopy. Leaf area was estimated from the surface of each leave using a direct and not destructive model. Ripening was monitored by evaluating the content of soluble solids, total acidity and pH from veraison to harvest. Samples of 20 kg of grapes were microvinificated, being evaluated by sensory analysis performed by expert judges. The results from the accumulation of sugars, pH and total acidity in the grapes not allowed to define the best treatments of leaf area. The fruty and vegetables aromas were the sensory attributes that best highlights the differences between treatments. The management of leaf area favored the reduction of the intensity of vegetal aromas in Merlot wine produced in Silo Joaquim. In this study, the intermediate level of leaf area (16F - 2.3 m2/kg) was the intensity of management best suited to evaluate the sensory quality of wines.