Effect of leaf removal on composition in Vitis vinifera L. cv. Tempranillo wine in Extremadura (Spain)

Abstract

Early leaf removal is a management technique applied to regulate crop load and improve fruit microclimate conditions in vigorous vineyards, increasing aeration and sunlight exposure in the cluster zone. This practice could affect the grape and wine quality and composition in red vine. The experiment was stablished in a full-irrigated vine (100% ETc) cv. Tempranillo located in Guadajira (Badajoz, Spain), and trained to a vertical shoot positioned trellis on a bilateral cordon system. This study analyzes the effect of leaf removal on physical and chemical characteristics of wines. Wines from defoliated vine (D) by removing the first seven basal leaves from each shoot before flowering were compared with those non-defoliated control (T) in a split-plot design with four replicates per treatment during three consecutive seasons (2009-2011).

The grapes of each plot were winemaking separately and standard parametres (alcoholic degree, titratable acidity, pH and potassium), phenolic composition (total polyphenols content, total and copigmentations anthocyanins, tannins and catechins) and colorimetric parametres (color intensity and color hue) were measured.

pH values, titratable acidity and malic acid concentration were affected by early leaf removal. The wines D had slightly decreased volatile acidity and improved alcoholic degree although in all these parameters is highly dependent of the season. Leaf removal increased the total polyphenol content and anthocyanins in a statistically significant level. The content of catechins, tannins, degree of polymerization and color intensity of wines increased, but not always in a statistically significant level.

In conclusion, year had the greastest impact on standar wine parametres although leaf removal improves wines quality mainly in the components related to the color.