HARVEST RIPENESS LEVEL HAS A LARGER EFFECT THAN LEAF
REMOVAL ON GRAPE AND WINE QUALITY IN CV. CABERNETSAUVIGNON FROM MAIPO VALLEY
LA FECHA DE COSECHA TIENE UN MAYOR EFECTO QUE EL DESHOJE SOBRE LA
CALIDAD DE UVAS Y VINOS CV. CABERNET-SAUVIGNON DEL VALLE DEL
VARGAS SOTO, Sebastián1; BORDEU, Edmundo2; CASAUBON, Gerard1; GONZÁLEZ ROJAS, Álvaro1* 1 Center for Research & Innovation, Viña Concha y Toro, Chile Departamento de Fruticultura y Enología, Pontificia Universidad Católica de Chile, Chile 2 *Corresponding author: firstname.lastname@example.org
Abstract: The effect of fruit zone leaf removal and harvest maturity level was studied in a commercial CabernetSauvignon vineyard in the Maule Valley (Chile) during three growing seasons from 2013/2014 to 2015/2016. Three factors were combined using a multifactorial yearly blocked design: (1) defoliation intensity, composed by two levels of leaf removal on the VSP cluster zone (a) 60% on the east side during pea size, and (b) 60% on the east side during pea size plus 40% on the west side during veraison; (2) type of defoliation, (a) hand-made or (b) mechanical; and (3) harvest maturity level determined by a commercial maturity tracking system, (a) fresh fruit profile and (b) ripe fruit profile. Research wines were processed with 700 to 800 Kg of fruit per treatment (24 experimental units). Measurements included climatic, physiological and canopy structural parameters as well as standard wine composition and phenolic characterization by HPLC-DAD. Compared to leaf removal, harvest maturity level had the highest effect on fruit and wine composition, by increasing must Brix and wine pH, alcohol, total tannins, color index, DO280, monomeric and total anthocyanins and by decreasing must yeast assimilable nitrogen and total acidity. Mechanical leaf removal was more severe than manual leaf removal, exposing the clusters more directly to the sun. The main effect of leaf removal was on must flavonols and monomeric flavan-3-ols, which increased with defoliation intensity.
Keywords: defoliation; mechanization; sunlight exposure; ripening; vine microclimate.