Temperature‐dependent responses of the berry developmental processes of three grapevine ( Vitis vinifera ) cultivars

The intrinsic relationship between grape berry ripening and temperature is not well understood. The aim was to compare ripening in three cultivars— Vitis vinifera L. cv. Chardonnay, cv. Merlot and cv. Semillon—in response to temperature. In the post‐veraison period (soluble solids 8–12 o Brix), whole vines were exposed to five controlled temperature regimes, with the day temperature ranging from 20–40 °C, and the berry attributes and the ripening processes followed. Temperature had little effect on the berry expansion process in all cultivars. However, there were marked effects of temperature on the accumulation of both dry matter and sugar in all varieties. The rate of ripening in all three cultivars was a curvilinear function of temperature. Rate of ripening of Chardonnay berries was highest at 25 °C and for Semillon and Merlot at 35 °C and 40 °C, respectively. Application of the temperature response to field‐grown Semillon vines accurately predicted the seasonal progression of ripening.