The part of the grapevine that is planted directly in the soil. Rootstocks from different varieties have different tolerances to disease and climatic stress and will be more or less suitable to a given type of soil. The variety of rootstock also affects how slowly or quickly the vine itself will grow. A vine need not grow from its own roots. In fact, most vines are not grown from their own roots but instead are grafted onto select rootstocks which have been bred for their disease-resistant properties (see PHYLLOXERA and VITIS).