Web Links
GENEVA APPLE ROOTSTOCK COMPARISON CHART
eXtension Apples Community of Practice
AFHRC Apple Rootstock Identification(broken link, arghhh...)
Characteristics of Apple Rootstocks and Interstem Combinations (PDF or Excel Update 10/2011: Prepared by Paul Domoto, Iowa State)
Apple Scion/Rootstock Selection and Planning for Michigan (aka tree spacing calculator)