Rootstock response of Shiraz (Vitis vinifera) grapevines to dry and drip-irrigated conditions

The yield and growth of Vitis vinifera cv. Shiraz scions grafted onto seven rootstocks were compared with that of own-rooted vines in a shallow sandy soil that was free of nematodes and phylloxera in the Barossa Valley of South Australia. In the absence of irrigation, own-rooted vines yielded as much fruit as vines grafted on Ramsey, the highest-yielding unirrigated rootstock-scion combination. Scions grafted to the rootstocks 110R, K51–40, 1103P and Freedom yielded poorly without irrigation. The yield and growth of all vines increased significantly when a small volume of irrigation water (40–160 mm/annum) was applied; however, only scions grafted to Ramsey and Freedom rootstock yielded more fruit than own-rooted vines.