Influence of water deficit on plant physiology, grape aromatic precursors and wine quality of Vitis vinifera L. cv. White Grenache

Abstract

Vitis vinifera L. cv. Garnacha Blanca (White Grenache) is the prior grape variety in the D.O. Terra Alta (Tarragona, Spain), where it has been recently irrigated; however, there are no studies about the most suitable irrigation scheduling and the consequences of irrigation on plant physiology and grape and wine aromatic profile.

The aim of this work, presenting preliminary results of a longer research, was to evaluate the effect of water deficit on grape and wine quality, focusing on grape aromatic precursors. To achieve this objective, four levels of water deficit were induced using different irrigation rates, from a no deficit treatment (ND) to rainfed (R), through two intermediate treatments, MD (moderate deficit) and SD (severe deficit), triplicated in the vineyard; irrigation for each treatment was scheduled weekly based on predawn water potential measurements (Ψ_pd).

Results showed significant differences between treatments in the photosynthetic net flux (A_N), and Leaf Area Index (LAI). There were also important differences in fruit yield, due to changes in berry weight. Grape berries and wines from ND treatment had higher values of both analytical parameters and sensory scores than those from stressed plants.