My 2016 apple rootstock trials - Western Maine z4b - M4, G222, G935, G969, B118

General Fruit Growing
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Hi all. I thought that I would post my results from my 2016 rootstock trial. This trial was for my own use, but I thought that someone else might find it useful. Zone 4b Maine growing conditions are quite different than much of the country, and rootstocks grow different than is often reported in warmer climates.

I trialed 4 newer rootstocks against the old standard Malling 4, which is becoming extremely difficult to find for some reason. If someone knows of a source of M4 in wholesale quantities, please let me know. To give perspective on how M4 grows in my area, it will easily grow 30+ feet tall if you let it.

This past spring, I grafted 5 different cultivars on each of these 5 rootstocks, and grew them in a row a couple feet from each other. The soil was not irrigated, but the water level is only about 10 feet below the surface. All of the the trees have now gone into dormancy, so I took measurements and took a few notes. Inches are rounded to the nearest quarter inch.

Malling 4
Average height increase = 29.75 inches
Notes: New wood is very flexible, which is a commonly known issue of M4, and should be staked for the first few years.

Geneva 222
Average height increase = 25.25 inches
Vigor: 85% of M4
Notes: New wood is very flexible, similar to M4.

Geneva 969
Average height increase = 25.5 inches
Vigor: 86% of M4
Notes: New wood is stiff, but can be bent without any feeling like it will crack. Bend it down and it snaps right back like a spring.

Geneva 935
Average height increase = 15 inches
Vigor: 50% of M4
Notes: New wood is stiff, but flexible to a point. Bend it too much and it feels like it will crack.

Bud 118
Average height increase = 23.75
Vigor: 80% of M4
Notes: New wood is stiff, but flexible up to a point like Geneva 935. 4 out of 5 roots had black lesions on them, which look to me like early stages of canker. Nowhere have I read that B118 is susceptible to canker, so maybe this is something else. Picture below.

20161020_133423.jpg1808Ă—2419 1.62 MB

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Can you rule out that that is not paint from the nursery? It sort of looks like when the nursery goes and marks trees with paint to tell them apart during sorting.

Otherwise I don’t know, but I’ve never seen canker before. It doesn’t look like disease where the tree has started any sort of healing process… The spot doesn’t look sunken at all, and the lenticels below the black look OK.

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That tree with the spot doesnt look like B118 to me. I grow alot of trees on it and the bark on B118 here has a dark reddish brown color.

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Its not paint. The black spots are dead bark. And the border between the living and dead bark is very distinct, which I have noticed on more advanced canker lesions. I bought the rootstocks through mailorder and I have never grown B118 before, so I was just assuming they were what they were labeled. But if the color is wrong, then I don’t know. They only rootstocks that I know for a fact is what I think it is, is M4, which I cut off from the bases of a couple old trees. None of the “B118” had any sign of any problems when I planted them this past spring, but now 4 out of 5 have these spots.

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Maybe the photo above didnt have good lighting, but I have seen photos of B118 online where the bark/cambium was the same color. So I am going to assume that my B118 rootstocks are actually that. I have also been told by someone who should know, that the lesion looks like Coryneum Canker. So I guess I wont be planting any B118. A shame since a lot of people in Maine supposedly love it. Oh well. My personal favorite rootstocks from the trial are Malling 4 and Geneva 969.

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I’m in Cumberland/Sagadahoc counties (coastal Maine, 5a/5b), and have put a handful of trees on what Fedco sold me as B118; if memory serves, it definitely has a red hue to the wood (and bark, IIRC) that you would have noticed in making up the grafts. I haven’t had issues with it here, but that’s with experience limited to about 10 trees.

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Hi Nick, I was wondering if you have an update on this trial? I’m especially interested in what happened to your B118, if that was a canker or not. Thanks!

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