INTERVENTI DI POTATURA VERDE PER LA GESTIONE DELLA MATURAZIONE DELL’UVA NELLA CV MERLOT IN AMBIENTE CALDO ARIDO

Considering the predicted scenarios of climate change for the near future, Mediterranean vineyards, may face substantial shifts in precipitation, atmospheric conditions and temperature, resulting in higher winter rainfall, together with drier and hotter summers. All potentially contributing to an uncoupling of technological and phenolic ripeness in Vitis vinifera grapevines, due to berry ripening taking place in the hottest month of the year, resulting in wines with high alcohol content and low titratable acidity. A reduced sugar accumulation rate in the berry may delay berry maturation and subsequently counteract these effects. The aim of this study was to delay berry maturation in cv Merlot, by altering the source-sink relationship at full veraison creating a source reduction by mechanical and hand leaf removal. Defoliated treatments compared to the control vines, stopped the vegetative growth, delayed berry shrinkage and sugar accumulation without altering must pH and titratable acidity and increased skin anthocyanin and flavonoids. It can be concluded that although the post-verasion source reduction approach holds great promise to study environmental phenomena like climate warming, careful planning and design of experiments are necessary, especially considering the time of treatment and harvest.