Late winter pruning
It is common knowledge that winter pruning applied fairly late in the season when buds have already begun to swell is effec- tive 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 promisingtoo 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 ).