Defoliation, application of S-ABA and vegetal extracts on the quality of grape and wine Malbec cultivar

Abstract High rainfall and low temperatures can cause grapes not to reach adequate maturation indexes. The aim of this work was to evaluate the effect of leaf removal, hormonal regulator and vegetable extracts on the quality of grape and wine. An experiment was conducted in a vineyard of Malbec cv.in southern Brazil by two consecutive seasons. Treatments were: 1) control, 2) manual defoliation in early maturation; 3) defoliation 15 days after the first defoliation; 4) S-ABA200 mg L-1; 5) S-ABA400 mg L-1; 6) S-ABA600 mg L-1. 7) vegetal Stachytarpheta cayenensis extract (100 g L-1) and 8) Cymbopogon citratus 100 g L-1. Diameter and length of canes, soluble solids, titratable acidity, anthocyanins and polyphenols in berry and wine, photosynthetically active radiation (PAR), chlorophyll index, defoliation percentage and leaf chlorosis and color index of berry skin were evaluated. Defoliation and S-ABA increased PAR. S-ABA provided leaf chlorosis and lowered the chlorophyll content, causing senescence. Defoliation and S-ABA increased the levels of total polyphenols, anthocyanins both in berry skin and wine of grapes Malbec cv. Vegetal extracts applied did not influence physical and chemical analyses, neither in anthocyanins and total polyphenols.