Desfolha, aplicação de ácido abscísico e de extratos vegetais na qualidade de uvas para vinificação

Abstract

Climatic conditions have a strong influence on grapevine cultivation. The high rate of rainfall and low temperature range, for example, can cause the grapes do not reach adequate maturation indexes. In order to check the effect of defoliation, the application of abscisic acid and application of plant extracts on the quality of grapes, two experiments were conducted in commercial vineyard with the cvs. Primitivo and Malbec, respectively, in Água Doce – SC. The treatments were as follows for experiment 1: 1) control (no treatment); 2) manual defoliation in early maturation (‘veraison’); 3) defoliation 15 days after the first manual defoliation; 4) abscisic acid 200 mg L-1; 5) abscisic acid 400 mg L-1; 6) abscisic acid 600 mg L-1. For experiment 2 were included two additional treatments: 7) gervão extract 100 g L-1, 8) extract lemon grass 100 g L-1. The following reviews were carried out: mass and berry diameter, diameter and length of branches, number and mass of branches, soluble solids, titratable acidity, soluble solids/acidity, pH, anthocyanins, total polyphenols, flavonoids, color intensity, photosynthetically active radiation, chlorophyll index, index of defoliation and chlorosis, lightness, chroma, hue, color index for red berries and alcohol content for wine. Defoliation and application of S-ABA showed no effects on the chemical characteristics of the bunches and berries in the two cultivars. There was a higher photosynthetically active radiation treatments of defoliation and S-ABA. The application of S-ABA provided chlorosis in leaves, followed by low chlorophyll content, causing the senescence, followed by defoliation. Defoliation and application of abscisic acid have provided increased levels of total polyphenols, anthocyanins, flavonoids and color intensity, both in Primitivo grape as the Malbec and wine. The plant extracts applied did not influence on the physical and chemical analyses, the anthocyanins and total polyphenols, flavonoids content only and intensity of color in cv Malbec.