Posted: 23/03/2016 at 07:30
Aronia, hawthorn and mountain ash are all rosaceae so theoretically compatible.
Tomatoes and potatoes are both from the solanum family as are aubergines which are also grafted together with the other two.
I think it's highly unlikely that grafting chokeberry onto an apple rootstock would change the nature of the growth pattern of the chokeberry. It might make it more or less vigorous than it would be on it's own roots, that is all.