Late winter pruning
It is common knowledge that winter pruning applied fairly late in the season when buds have already begun to swell is effective at postponing bud-break by a few days therefore helping at escaping spring frost (Coombe,1964;Howell and Wolpert,1978).Nowadays, a further postponement of winter pruning date seems a quite promising tool to delay ripening.Friend and Trought (2007)working on Merlot grown in New Zealand have shown that winter pruning applied when the upper part of the canes already bears shoots ∼ 5 cm long, decreases berry TSS by up to − 3.6 ◦ Brix, slow down the degradation of acids and helps to maintain an optimum must pH. A preliminary work ( Palliotti et al., 2014b ) on spur-pruned cv. Sangiovese has shown that postponing winter pruning to begin- ning of May (BBCH55, i.e. inflorescence swelling and flowers closely pressed together)caused a significant decrease of yield per vine anda delay in TSS accumulation as compared to vines pruned at BBCH0 (dormancy) and BBCH1 (beginning of bud swelling) ( Table 2 ; Fig.3 ). Compared to these latter treatments, BBCH55 pruning reduced the number of inflorescencesper vine (8.9 vs. 13.4), determine a decrease in fruit-set (93 vs. 118 berries/ and berry (2.20 g vs. 2.72 g) and bunch weight (203g vs. 316 g). The analysis of the kinetics of grape ripening showed that vines pruned on early May had a marked ripening lag and, at harvest, the TSS content in the must was of nearly 1.1 ◦ Brix lower than the other treatments, while the titratable acidity was higher by about 1.8 g/l ( Table 2 ; Fig. 3 ).