Deficit irrigation differently affects aroma composition in berries of <i>Vitis vinifera</i> L. (cvs Sangiovese and Merlot) grafted on two rootstocks

Background and Aims Water deficit modifies the concentration of aroma compounds grape berries, but little information is available on effect deficits applied at different phenological stages. We evaluated irrigation glycosylated volatile organic (VOCs) responsible for berries Sangiovese Merlot cultivars grafted 1103P or SO4 rootstocks. Methods Results Vines were subjected to either pre- post-veraison water stress, berry composition compared against that fruit fully irrigated vines. At harvest, a higher VOCs was measured in from vines stressed pre-veraison, while it increased as Sangiovese, this occurred only low moderate level stress Merlot. Post-veraison had negative negligible harvest. The rootstock affected VOCs, particularly with observed than Conclusions Pre-veraison enhanced did not. rootstock–scion interaction might amplify VOCs. Significance Study Modifying timing volume allow management flavour improved wine composition. Irrigation protocols should be tailored specific cultivar–rootstock combinations.