A. Sabir - University of Selcuk, Faculty of Agriculture, Department of Horticulture, ۴۲۰۷۵, Konya, Turkey.

Plant growth and reproductivity of grape cv. 'Italia' subjected to two different irrigation levels in controlled glasshouse were investigated over ۲ years. Initially, two years old vines were grafted on ۵ BB (V. berlandieri Planch.×V. riparia Michx.), ۹۹ R (V. berlandieri Planch.×V. rupestris Scheele) rootstocks or on its own root system in ۴۰ L pots. During the cultivation, half of the vines of each experimental group were Fully Irrigated (FI: ۱۰۰% of field capacity) while the others were subjected to continuous Deficit Irrigation (DI: ۴۰% of field capacity). During the study, significant negative effects of DI on plant vegetative development and physiology were observed. The lignified shoot length of vine on ۵ BB rootstock decreased by ۲۹.۱% under DI as compared to growth under FI. On the other hand, the vine with ۹۹ R rootstock decreased by ۱۸.۲% under DI as compared to lignified shoot growth under FI, while a ۲۰.۱% decrease occurred for own root (DI vs. FI). Also, DI regime resulted in slight decreases in P, K, and Ca status of leaves, while Zn and Cu concentrations were significantly higher in the vines subjected to DI. DI resulted in reduced cluster weight and vine yield in varying degrees with respect to rootstock usage. Under DI condition, the vines on ۹۹ R yielded better than those on ۵ BB, but vines on on ۵ BB reacted adversely to DI. Considering the overall findings, grapevines cv. 'Italia' on ۹۹ R exhibited higher drought tolerance than ۵ BB. Rootstocks had slight impairing effects on physiological traits, yield, and mineral acquisition of grapevine cv. 'Italia' as compared to own-rooted.

Grapevine, Deficit irrigation, Rootstock, Vitis spp