Management of carbohydrate reserve accumulation as a tool for regulating vine productivity and fruit quality

Carbohydrates play a critical role in grapevine growth and development, and many viticultural practices such as crop load regulation, canopy management and deficit irrigation are essentially modifying the relationship between carbohydrate sources and sinks. However, the role of carbohydrate reserves in the overall carbon economy of the vine has not received much attention despite the importance of stored carbohydrates for early canopy development, and the demonstrated capacity of reserves to contribute to berry ripening. This work aimed to provide a better understanding of the role of carbohydrate reserves in grape production through four complimentary studies. The first involved the excavation of whole grapevines to quantify the size of various reserve pools, and the concentration dynamics during the season. The second study involved a survey of 34 Shiraz and Chardonnay vineyards over three years to characterise the seasonal variation in carbohydrate reserves, and the third evaluated practical methods for manipulating reserve accumulation and fruit composition in Shiraz and Chardonnay. The final experiment was conducted with pot grown Chardonnay using controlled environment conditions to clarify the relative importance of carbohydrate reserves and current photosynthesis for fruit-set in grapevines.