Leaf removal and cluster thinning trials in "Foglia Tonda" grapevine.

The research was carried out in the 2015 growing season in order to optimize the qualitative expression of the native Tuscan cv. Foglia Tonda (Vitis vinifera). The effects of three different treatments for yield control in comparison with the untreated (CTRL) were analyzed: two intensity of early leaf removal achieved at the end of May (4 and 6 leaves removed, respectively 4LR and 6LR) and cluster thinning (CT) at veraison in August. Investigation in productive activity, qualitative and quantitative grape’s characteristics were carried out: from the veraison to harvest, berry samples were collected and sugar content, titratable acidity, pH, extractable anthocyanins and polyphenols were analyzed. Concluding, results showed that cv. Foglia tonda is a very productive variety and therefore is useful to decrease yield excess, with early leaf defoliation or cluster thinning. Overall, early defoliation may be an excellent tool for yield control, replacing time consuming of manual cluster thinning.