Vegetative and Reproductive Growth Responses of Gra pevine cv . 'Italia' ( Vitis vinifera L.) Grafted on Different Rootstocks to Contrasting Soil W ater Status

Abstract

Plant growth and reproductivity of grape cv . 'Italia' subjected to two different irrigation levels in controlled glasshouse were inv estigated over 2 years. Initially, two years old vines were grafted on 5 BB ( V. berlandieri Planch.× V. riparia Michx.), 99 R ( V. berlandieri Planch.× V. rupestris Scheele) rootstocks or on its own root system in 4 0 L pots. During the cultivation, half of the vines of each e xperimental group were Fully Irrigated (FI: 100% of field capacity) while the others were subjected to continuous Deficit Irrigation (DI: 40% 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 5 BB rootstock decreased by 29.1% under DI as compared to growth under FI. On the other hand, the vine with 99 R rootstock dec reased by 18.2% under DI as compared to lignified shoot growth under FI, while a 20.1% decrease occurred for own root (DI vs. FI). Also, DI regime resulted in sligh t decreases in P, K, and Ca status of leaves, while Zn and Cu concentrations were signifi cantly 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 9 9 R yielded better than those on 5 BB, but vines on on 5 BB reacted adversely to DI. Consi dering the overall findings, grapevines cv. 'Italia' on 99 R exhibited higher drought toleranc e than 5 BB. Rootstocks had slight impairing effects on physiological traits, yield, a nd mineral acquisition of grapevine cv . 'Italia' as compared to own-rooted. Keywords: Grapevine, Deficit irrigation, Rootstock, Vitis spp.