Several times while researching apple rootstocks I've encountered the comment that "many triploids, when grafted onto [Malling 26] may exhibit signs of graft union incompatibility...." (That quote from a Penn State site, for example.) This appears to manifest itself in a breakage at the graft union under somewhat windy conditions where other apples would not be affected. However, I've only ever seen the general statement but have nowhere been able to find a list of specific triploid apples that are known to be affected.
This is a bit frustrating because a surprising number of my favorite apples happen to be triploids but I have no way of knowing which might be susceptible. Several triploids that I've grafted to date are on M or EMLA 26 (with no breakage as yet), but I think I may just have to make future grafts of triploids onto MM 106 or 111 to avoid an unforeseeable event in the future. Those of you active on the HOS site no doubt have much better web search skills than I. Have any of you ever encountered a list of the specific triploids known to be affected?
Hi Reinettes,
I agree that many triploids are among the greatest of all apples. Karmijn, Belle da Boskoop, and Jonagold come to mind.
I have never heard of this situation, nor experienced it, but I'm glad you said that. I would assume that you could graft one non-triploid variety to the M-26 or and then the triploid onto the non-triploid variety. We do that one with quince rootstock and non-compatible pear varieties. It works well. That's how I would take care of the situation. I'm sorry that I can't give you anything on your already grafted trees.
I have had two loaded triploids break on dwarf stock, both below the graft union, so you can see how I don't want to graft large or triploid apples onto dwarf stock.
John S
PDX OR
Ah, an interstem between the M.26 and the [potentially susceptible] triploid. Now why didn't I think of that? Good call, John. Obviously it pays to get input from others and break me out of my tunnel-vision.
When you say you've had breakage of fruit-laden triploids on dwarf rootstock, which rootstock are you talking about? Something like P.22 or M.27?
--Tim.
Idyllwild
simplepress
jafar
Marsha H
Viron
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