Rootstock Effects on Primary Bud Necrosis, Bud Fertility, and Carbohydrate Storage in Shiraz

Abstract

Shiraz grapevines (Vitis vinifera L.) grafted to three different hybrid (American Vitis) rootstocks at two sites were used to evaluate the effect of rootstock on primary bud necrosis (PBN), fruitfulness, and carbohydrate storage. Buds were dissected during winter dormancy and assessed for the number of inflorescence primordia and incidence of primary bud necrosis. Trunks, canes, and roots were sampled at dormancy for carbohydrate concentration. A water deficit treatment was also applied at one of the two locations. Fruitfulness and yield were affected by water deficit. Rootstock type influenced the incidence of primary bud necrosis, fruitfulness, and carbohydrate concentration at both sites.