Evaluation of interactive effects of mechanical leafing and deficit irrigation on berry composition and wine chemistry of Vitis vinifera cv. Cabernet Sauvignon Grown in the San Joaquin Valley of California

Mechanical leafing at bloom and berry set either on one side or both sides of the canopy does not affect the final yield. Leafing, either on bloom or berry set, improves the anthocyanins accumulation during the ripening and increases the harvest berry anthocyanins. Light exposure resulted from bloom leafing only lasts for approximately 2 weeks, and such a short period of light exposure during/after bloom is enough to increase the anthocyanins accumulation and final berry anthocyanins. Overexposure from berry set leafing might promote the anthocyanins degradation at the end of berry ripening.

Water deficit during cell growth stage I, from berry set to veraison, reduces berry size and ultimate yield, although the decline of berry size and yield depends on the severity of water deficit during the stage I. Water deficit increases the harvest berry anthocyanins, although its increase mainly results from the high skin/pulp ratio associated with small berry size.

From research wine micro-fermentation, resulted wine color follows the similar pattern of harvest berry color.