Fascinating info. Observant grafters have long noticed that interactions vary considerably between individual stock/scion combinations. I tried a new cultivar that died to the trunk most winters. After five or six years of that, I concluded it wasn’t hardy enough here and regrafted with something that is. But I decided to give it one more chance and grafted it on a frankentree, where it thrived and bore fruit in a couple years. It’s never shown any trace of winterkill, and I’ve also grafted it to other stocks with no problem. As for the original stock, the replacement also thrived and is now bearing. Apparently there were some personality conflicts going on. A bit of divorce and remarriage solved that!
Here is an interesting example demonstrating the interactions between stock and scion. I think it’s from one of Niels Hansen’s publications:
