I’m not convinced that the wild persimmons on my place are 60 chromosome. I didn’t know there were any visible attributes like fuzzy leaves to distinguish between 60 and 90 chromosome strains. I do know that someone in eastern Tennessee (kind of near Asheville, NC) – and I think Hillbillyhort in WV, too, right? – is able to grow a bunch of the popular named varieties of American persimmons and get seedless fruit, but I get fully seeded fruit from varieties like Meader and Ruby here, and a friend in nearby Winston-Salem gets fully seeded fruit from Yates… Have you gotten any fruit from named American persimmon varieties at your place yet, Ben? Theoretically if you’re in the 60 chromosome area you ought to get mostly seedless fruit, right? I’m not hopeful for you, though. It’s a poor guess, but my best guess is that my wild persimmons are 90 chromosome. What else could explain me getting all fully seeded fruit?
But even if I am in the 60 chromosome region as conventional wisdom suggests (south of the Ohio River) – and I’m pretty close to due south of Hillbillyhort in WV that’s apparently far enough south to be in the 60 chromosome region – my grafting failures are inconsistent like Hillbillyhort has described. Some grafts take. Others don’t. But one thing that seems consistent is that if an Asian or Asian hybrid graft fails (typically by initially growing and then turning black and dying after putting on 6-12" of new stem growth) subsequent grafts on that same rootstock seem to never take. Maybe it’s an old rootstock issue like Dave is guessing. Almost all of the rootstocks I’m grafting onto are volunteers that have been mowed 1-3 times per year for decades, so although the top growth is only 2-3 years old, I think the roots on the trees I’m grafting on could be 50 or 100 years old. Most of the volunteer trees I’m using as rootstock grow in clusters that I believe are all root suckers off of the same root system. I’d guess only about 10% of my Asian grafts show signs of incompatibility like I described.
This year, for the first time, though, I had some branches on established trees (one Saijo, one Sheng) show the same symptoms, but in neither case was it the whole tree. These are trees I grafted 4-5 years ago that never showed any symptoms before. The Saijo was a forked tree, so I just cut out the whole fork with the diseased looking branches. I haven’t done anything with the Sheng yet. It’s curious to me that this happened this year, because we had a mild winter and a spring exceptionally free of any late freeze/frost events, so there doesn’t seem to be any correlation at all to winter injury.
Whatever problems you’ve had, Ben, my guess is that they don’t have anything to do with 60/90 chromosome differences, but I don’t have a good guess as to what else it could be.