Regulation of berry quality parameters in 'Shiraz' grapevines through rootstocks (Vitis)

The concentration of potassium (K) and pH in juice of grapevines is influenced by rootstocks (Vitis). However, the performance of rootstocks with respect to berry quality parameters and inter-relationships among berry quality parameters are not well understood. The current study addresses these issues. Berry and leaf samples at harvest maturity were collected from mature field-grown 'Shiraz' grapevines grafted with each of the rootstocks Dogridge, Freedom, Ramsey, 1103 Paulsen and 140 Ruggeri. Concentrations of K in juice and petiole and pH in juice were each highest for Dogridge and Freedom, but lowest for 140 Ruggeri and 1103 Paulsen. High concentration of K in juice was related to high concentrations of malic acid and TSS but low tartaric acid/malic acid ratio. In this study, lower concentrations of K in juice and in turn pH in juice of 'Shiraz' grapevines were maintained through rootstocks such as 140 Ruggeri and 1103 Paulsen that also show lower concentrations of K in petiole and TSS in juice, and higher tartaric/malic acid concentration ratio in juice at maturity. Selective use of these rootstocks in turn helps to produce quality grape juice and wine