Search

Mestrado Vinifera Euromaster - Viticulture and Enology - Instituto Superior de Agronomia - UL / Institutt National D'Etudes Superieures Agronomiques de Montpellier This paper studies whether pre-flowering basal leaf removal is able to modify the cluster compactness in Vitis vinifera L. cv Trincadeira, as well as its berry composition and canopy density, in order to avoid the incidence of diseases such as Botrytis bunch rot. The first six leaves were removed for an early defoliation treatment (ED) performed at pre-bloom, and this was compared with a control non-defoliated (ND). During the vegetative season, various analyses were performed: monitoring phenology development, leaf area measurements, radiations analysis, stem water potential, canopy dimensions and Point Quadrat assessments, fruitfulness, bunch compactness estimation and berry composition. Results seem to point out that early defoliated vines went through a prompt recovery, with a great lateral shoots and leaves regrowth. Despite no significant difference was proven in the analyses from the two treatments, leaf area and canopy dimension appears to be greater in ND vines all along the season up until ripening, when ED vines show higher values. Clusters affected by coulure and millerandage were found both in ED and in ND vines, demonstrating that fruitset was not optimal in the whole plot. Trincadeira’s high vigor and unsuitable environment conditions during 2016 season were found to have a greater impact than expected. Significance of the study: The goal is to provide viticulturists with tools to optimize the wine grape production, using a feasible field operation. N/A

Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia - UL With the goal to improve the characteristics of the grapes, a Cabernet sauvignon vineyard in Maule valley (Chile) was subjected to 5 different typologies of defoliation compared with a control not defoliated. Different timing and quality of defoliation were analysed. It was also compared a kaolin based product to reduce the warming effect of the direct light on the clusters. The study of the canopy, through the point quadrat and the leaf area analyses, gave objective parameters and enabled to have a repeatibility on the years. The amount of light in the canopy and the temperature of the clusters were registered for each treatment in three different occasions. At the harvest the berries were counted and divided according the dehydration to understand the damage done by the sun. The influence of the light and the temperature was studied on the chemical composition of the musts of the vintage 2016 and on the wines of the vintage 2015 to find the best correlation between the solar exposition and the quality parameters of the grapes as the flavonoids. The 2015 wine resulted from the same trial was also sensory analysed by a panel to find additional differences between the treatments. If on one hand, the solar light allows to diminish the quantity of green aromas and to improve the chemical characteristics, an over-exposition could be dangerous for the grape. The aim of this study was to find the right compromise to have the benefit of the light without the damage of the heat. According to this research a total defoliation of the cluster zone during the veraison could be a damage for the yield and the sensory characteristics of the wine. On the other hand the “no act” philosophy of the control doesn’t seem a valid solution because it has the worst sensory results. Seems that in this South American context, the best solution could be a treatment that allow the exposition to the light of the cluster avoiding the hottest hours of the day and limiting the warming of the berries N/A