I often wondered if one could get the best of both worlds by planting a tree on Bud9 or other fast fruiting clonal rootstock with the graft just an inch or so above the ground. Then, after the tree was fruiting well, mound a foot or so of soil tapering out from the tree so the graft was well covered. Over time, the tree would produce roots above the graft. The question is, would this tree revert to a vegetative state and stop production until I was larger, or if would continue good production as it grew?
I haven't tried this, but I've always wondered about it.
The reason I'm not sure is because of an experience I had with Jujube. I planted some bare root Tigertooth grown on their own roots. After the trees were a few years old, I propagated them from root cuttings. I grew the root cuttings in root pruning containers on my deck. In the very first growing season they produced fruit even though the parent trees took another 4 years to produce. I ask a Jujube expert about it from one of the universities. His explanation was that the root constraint caused by the root pruning containers caused the young trees to change from a vegetative state to a fruiting state. He suggested that once they were planted in the field and the roots were free to range, they would revert to a vegetative state for several years before fruiting. He was right. They have been in the field for several years now and have not fruited.
Thanks,
Jack