Use of a resistant, or tolerant, rootstock, developed by Charles Valentine Riley in collaboration with J. E. Planchon and promoted by T. V. Munson, involved grafting a "Vitis vinifera" scion onto the roots of a resistant "Vitis aestivalis" or other American native species. This is the preferred method today, because the rootstock does not interfere with the development of the wine grapes (more technically, the genes responsible for the grapes are not in the rootstock but in the scion), and it furthermore allows the customization of the rootstock to soil and weather conditions, as well as desired vigor.