I'll bet you can- but that's no guarantee. I mention from time to time my experiment grafting a prune plum to Nanking cherry (prunus tomentosa). It's entering its third year and appears to be healthy but quite dwarfed. We'll see what it does this year and next, if there is a next. Stone fruits often are compatible, but even so, there can be issues of delayed incompatibility, so you might not have your final answer for years. But I want to hazard a guess and a possible objection to your plan: it might work better to graft a more developed plant to a more primitive plant than the other way around, and it might work better to graft to a "forebear" than to a "cousin". In other words, I'm guessing that the wild host plant might work as a rootstock to more than one descendant but the reverse might not be true, and while two different fruits might graft to a common descendant they might not be cross compatible! i'm just thinking aloud on this- anybody actually know? I'd like to know. Good luck, and thanks! :-)M

Today January 2, I dug up Comte de Chambord, grafted of Multiflora rootstock. Bluegirl had it for a few years in her alkaline Texas, didn't bloom well so she gave to me, since I have more rain. As multiflora-rootstock, Comte bloomed OK in spring but stingy afterwards, while my 2 other Comte as OWN-ROOT bloom profusely with 4 flushes until snow hit. I have Comte-on-multiflora for 2 years. It's so stingy in the summer I moved it next to the rain-spout in July. Its root was the same size as my marigold !! It became even stingier, despite my using the entire bag of coarse sand to make my clay fluffy. So I dug up Comte grafted on multiflora today, Jan 2, and IT WAS THE MOST PATHETIC multiflora rootstock that I had ever seen in my 3 decades of growing roses !! I already posted the study that showed Fortuniana-rootstock produces more blooms than Dr. Huey, and Dr. Huey produces more blooms than multiflora-rootstock. Left side is Comte de Chambord grafted on multiflora rootstock, right side is a snapdragon annual flower root (sown from seed !!). The snapdragon-flower root is actually larger than the multiflora-rootstock. This 4+ year-old Multiflora-rootstock actually SHRANK in my alkaline clay, despite tons of acidic rain. And it REFUSED to give me own-roots at the side like Dr. Huey-rootstock. Picture taken today, Jan 2 at 39 F or 4 C. Re-post info. from Oct. 2016: Comparing Dr. Huey-rootstock, Multiflora-rootstock, and Fortuniana-rootstock from below link, worth reading: http://roses4az-mevrs.org/wp-content/uploads/An-Overview-of-Fortuniana.pdf Here in the Desert Southwest, with our generally alkaline soils and extreme temperatures, we find that r. multiflora has a shorter life span, losing its vigor after five years. While fortuniana bushes had superior root systems, they had difficulty with the harsh & cold English climate. In a study over several years, Dr. McFadden budded two hybrid tea varieties, Queen Elizabeth and Tiffany, onto three different rootstocks. After counting the number of blooms produced over many growing seasons, the varieties budded onto fortuniana produced significantly more blooms. The fortuniana plants produced about THREE TIMES the number of blooms as those on multiflora and TWICE as many as on Dr. Huey. Additional benefits of Fortuniana include increased resistance to gall, stem dieback, and root disease, such as Phytophtora and Pythium. Bushes planted over 40 years ago in Florida are still thriving. On this rootstock, plants are heavier feeders, as they have five times the feeder roots of more common varieties." http://roses4az-mevrs.org/wp-content/uploads/An-Overview-of-Fortuniana.pdf

That's completely understandable. We are all "virgins" at everything once. We worry about the first child, the first dog or cat, the first rose, dahlia, orchid, etc. and why wouldn't we worry about the first newly budded plant? We don't want to kill or otherwise injur it, but by the time you have the second child, second dog, second rose, you don't worry about them because you've learned they're going to thrive in spite of you! Thanks. Kim

It's cut and dried if you can see the graft union. That's all that counts. But even if growth is from above the graft union, I'd question whether the trees are worth any further investment of time and money. Especially for a commercial venture. If it were just 1-2 trees I'd say take a chance.