Apple growers first became interested in grafting scions onto rootstocks when they realized that dwarfing rootstocks could tame vigor, bring trees down to manageable size, and cause them to bear fruit earlier. The question, “How do rootstocks do that?” was never fully answered. And a new question is becoming important: “What else might they do?” Some of the new rootstocks coming from the breeding program in Geneva, New York, are able to confer whole-tree resistance to the pathogen complex called replant disease. In the future, growers may be able to choose a rootstock that would greatly increase calcium uptake and […]