ROOTSTOCKS

 

Today, almost all commercial varieties of wine grapes are grafted onto phylloxera resistant rootstocks. These rootstocks are often produced from hybrid crosses of the following parent varieties:

Vitis rupestris: A native of the eastern United States which provides vigor.
Vitis berlandieri: A native of the dry southwestern Unitied States which provides drought tolerance.
Vitis riperia: A native of the northeastern United States which provides cool weather tolerance.

Another rootstock which provides some tolerance to Xiphinema index nematode, the vector of fanleaf virus, is a cross between Vitis rotundifolia and Vitis vinifera.