Effect of canopy management on Merlot grape quality in Bolgheri

Abstract

The objective of this trial was to improve the quality of Merlot grapes, through the canopy management, to achieve better phenolic maturity without increasing the sugar content of the grapes. The vineyard located in Bolgheri (Tuscany-Italy) consisted of the cv. Merlot (clone181 on 110R) spaced at m 2.0 x 0.7, trained to horizontal spur cordon, pruned to 8 buds per vine, which were subjected to three types of canopy treatment on six randomized replications: FM) current farm management consisting of three shoot trimming (topping and hedging) made every 20 days, starting from the beginning of June (after fruit set); ELR) early basal shoot leaf removal at bloom followed by three shoot trimming every 20 days (like in treatment FM); NTD) None shoot trimming nor defoliation, rolling up the terminal part of the shoots, as adopted in biodynamic viticulture. The early defoliation determined a decrease in the number of berries per bunch (-17%) and the size of grapes at harvest (-15%) compared to the other thesis, moreover, did not affect the level of sugar at ripeness, leading to a significant increase of the phenol content (polyphenols, anthocyanins and total anthocyanins extracted). Instrumental analysis of phenol substances were perfectly compatible with those obtained by the of sensorial analysis panel which tested the berry maturity using a new method developed by our Department. More precisely a better cellular phenol maturity (skin and seed) and a greater attenuation of the bitter taste on berry sampled by the vines early defoliated were detected.