COMPARISON OF CABERNET-SAUVIGNON AND CABERNET-FRANC GRAPEVINE DORMANT BUD COLD HARDINESS

Cold hardiness of 'Cabernet Sauvignon' (CS) and 'Cabernet franc' (CF) dormant buds was compared during two winters by thermal analysis of bud freezing events. The vines were of the same age and planted in adjacent blocks of a northern Virginia vineyard. CF buds were typically one to two degrees (C) hardier than CS buds except in spring, when CF buds deacclimated more rapidly than CS buds. The general pattern of superior cold hardiness of CF buds is consistent with limited grower experience with whole-vine responses of these two Vitis vinifera cultivars to low temperature stress in the field.