Basal leaf removal to reduce fruitset and induce smaller and looser clusters in variety Trincadeira with compact bunches

Mestrado Vinifera Euromaster - Viticulture and Enology - Instituto Superior de Agronomia - UL / Institutt National D'Etudes Superieures Agronomiques de MontpellierThis 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/