Influence of water stress on grape quality and aroma precursors in Sauvignon Blanc grown in Bolgheri area (Tuscany)

Climate change has a direct impact on the phenological stages of the grapevine, with consequences on the anticipation of aging and on the qualitative characteristics of the grapes. In fact, there is a decrease in the skin/pulp ratio, with possible reduction of the aromatic potential. This work was aimed at assessing the effects of water stress on technological maturity and thiol precursors of Sauvignon Blanc grapes in two vineyards of Bolgheri. To this purpose, 3 theses have been established: WW, well watered; WS, moderate stress; CTRL, control. During the season, measurements of single leaf gas exchange, stem water potential were made; moreover parameters of technological maturity (° Brix, acidity, pH and berry weight) and thiol precursors were analyzed. As expected, the water potential was less negative in the irrigated thesis due to the greater availability of water, as well as the highest rates of photosynthesis, transpiration and stomatal conductance. Technological analyses showed no significant differences among the treatments. The analysis of the 3MH/3-mercaptoesan-1-ol precursors showed that the WW had a greater accumulation than the other theses. These results suggest that lower water stress favors a better aromatic content.