The influence of pruning date on yield control and ripening rate of spur-pruned Sangiovese grapevines was investigated over two years (2013 and 2014). Winter pruning was applied on February 1,4 (mid-dormancy); March 1,5 (late-dormancy); April 2,7 (bud swell); May 2,7 (flowers closely pressed together) and June 1,6 (40–50% of flower caps fallen). Vine yield and fruit composition at harvest were not affected by shifting from the standard pruning dates of mid and late dormancy to the bud swell stage. By contrast, the number of inflorescences from compound buds was significantly reduced for vines pruned early May. No inflorescences were retained on vines pruned at the beginning of June. Early May pruning reduced fruit-set and berry weight, and fruit ripening was slower when compared to the other pruning dates. At harvest, must soluble solids and titratable acidity were 1.6 Brix lower and 1.8 g/l higher, respectively, for the May treatment as compared to the standard pruning dates. The early May pruning dates also achieved higher total anthocyanins and phenolic concentrations than the standard pruning dates, indication that this technique can potentially decouple the accumulation dynamics of these components. Further studies are needed to better calibrate winter pruning date for managing yield and berry maturation rate.
- ©2016 by the American Society for Enology and Viticulture