Low genetic diversity of Geneva rootstocks and viruses

Over on the Scion Exchange Facebook page, someone brought up the the potential for Geneva rootstocks to be susceptible to latent viruses in the scion.

So far we know that G.30, G.16, G.935, G.814 (doesn’t seem commonly available to hobbyist), are all potentially susceptible to latent viruses, at least to some extent.

Given the low genetic diversity of Geneva rootstocks, this seems like it could be a real problem for those of us grafting traded varieties of scion. Most of the Geneva roots are from crosses of Ottawa 3 and Robusta 5 parents.

Geneva roots without Ottawa 3 parentage are: G.11, G.41, G.202.

If one looks at this table: you can see that Ottawa 3 is a rootstock that is suceptible to latent viruses. So the low genetic diversity of the Geneva stocks might predict a broader susceptibility to viruses than is known so far. …?


Is this a problem with scions from nurseries on these rootstocks, or are we talking about putting your own scions onto these RS that is more risky?

I have three trees on G16, one on G30, and a couple more coming next month on G30. All of these are Cummins trees.

I suspect it is much more of a concern with putting your own scions onto those rootstocks. Unless they completely have their head in the sand and are drunk on their own cool-aid, I’d think Cummins would try hard to not sell virus-infected plants. That should especially be the case for G.16 where it is very well noted everywhere on the interwebs, and their own website that it is virus-susceptible.

Yes, Cummins is very careful on what they put on G16 etc. But I personally am never buying anything on it again since I often am changing varieties around. I lost 10 or more G16s.

Thanks for pointing out the Ottawa 3 ancestry, I’m going to avoid any of those children. Most of my issues have been with G16 but I had a few G30s so south as well.

With rootstocks never forget the advantage of the tried and true. The longer a stock has been around the better it often is. I have seen too many rootstocks praised to the skies at introduction, and damned ten years later.


Latent viruses suddenly becoming an issue is another reason I’m not sure I would invest in a super high density orchard. The initial savings in planting a traditional orchard of dwarf or semi dwarf more than pays for the land around here.

Yeah, I have been really for the Geneva roots given their quick turnaround from whip to fruiting, and their supposed fruiting efficiency. Most of my apples are on Geneva roots (or M7), and all of them will have other grafts on them after this year, I think. But looking holistically, if this virus issue turns out bad, then the G roots might have been a bad choice.

M7 is a very old rootstock. If I hadn’t been so opposed to staking when I first planted trees, M9 would have been a better choice. I’m realizing that M7 is going to be too big for the trees’ space. (M26 being too susceptible to root rots for my location.)

Also for me, if I ever got fireblight so bad that it killed the scion, I’d pull the whole tree out and send it to the dump rather than risk re-infection. So FB resistance of the roots isn’t that big of a deal.


Those following this topic may find this article interesting: Problematic pairings with Geneva 935


Thanks for posting this information, everybody, and particularly to Drew for the explanation about the Ottawa 3 ancestry of the problematic Geneva rootstocks. I had originally ordered G 935 rootstock for the grafting that I’m planning to do with my dad this spring, having read very positive reviews of it’s performance from others here. But after reading this and the earlier thread about virus-infected scion wood, I decided to change my order to G 41, which sounds like it doesn’t have the same issues with virus sensitivity. (I’m aware that there’s some question about how big of a problem viruses are likely to be in a home orchard setting. On the other hand, it sounds like home grafting is more likely to lead to problems with susceptible rootstocks down the road.)

@scottfsmith, it sounds like you’ve had particularly bad results with (some of) the Geneva rootstocks. Just to confirm, was it particularly G16 and G30 that turned out badly for you? Do you attribute that mainly to multi grafting with infected scions, or do you suspect that there were other factors involved?

@Vohd, very interesting article, thank you for posting the link. It seems like the takeaways are (1) viruses are suspected to be a problem with G 935, (2) but they may not be the only or even the primary culprit for the problems that have been observed - possibly poor rooting? (3) certain strains and varieties may be particularly problematic on G 935, others less so. (Honeycrisp in particular sounds like it can be less than fun.) Of course, the results they’re reviewing come from a commercial orchard setting and don’t speak directly to the issue of grafting traded or open-sourced scions.

Anyhow, thank you all for guiding me away from a potential Marvin the Martian moment down the road. I will find many more ways of getting there, I’m sure…

Oh, and by the way, Drew - Go Hawks! I was born in Iowa City - my dad got his MFA in art there.


I have an issue with the G11 and G202 splitting/cracking right before the graft. I have two of each as my rootstocks on apple trees. We had a drought for about 6-8 weeks then we received 5" of rain in a short period of about 5 days. Each one of these Geneva rootstocks split and cracked. I have many other rootstocks on other apple trees and none of those split. Just the Geneva rootstocks. I am staying away from the Geneva series for my orchard. Sounds like there are other issues as well from the articles provided here. Thank you for the information.

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Sorry to hear about your Geneva rootstocks. I have two trees (Liberty + Winecrisp) on G202, planted last year, and I just planted an Alkmene on G11 this year. Hope I don’t see the same problems you had.

My Winecrisp is my only apple so far that has bloomed besides our Winesap. But all our apple trees are just now really starting to leaf out. The Liberty seems to be doing well also. The Alkie has tons of purple little buds on it already, even tho I just planted it a month ago.

We don’t have any trees on G935, I would have liked to have tried some on this RS, but ended up with G30 instead.

We planted three new apple, two pear, and two peach trees, and it looks like they’ve all pushed out some greenery, a good sign.

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I was very disappointed at the Geneva rootstocks all doing that. I was so hopeful they were the answer to the rootstock choices I was making. Most of all the others I have are on M111. It is an OK rootstock but there are several issues with it. I HATE suckering at the rootstock and the M111 seems to be bad at that. I am getting too old to be bending down cutting those off month after month with some pruning shears. Even my ornamental crabtrees and magnolia trees have a ton of root suckers that have to be cut off.
I hope you have better luck with the Geneva rootstocks than I have had. I probably will not buy any more of them. I hate for the possibility of having a little older fruit producing tree die because of something with the G series being used. That is a lot of time to make up for starting a new fruit tree if you have to remove it.
Alkie? What variety is that?

Perhaps I misunderstood, but it wasn’t ALL Geneva rootstocks, just the specific ones listed. The others are crosses of the problematic variety.

So far that are just the ones they have noted. In my situation this issue has not been listed any where I have seen. Yet, I have never seen this type of cracking and rootstock separation in my 40 years of growing and being around fruit trees. Both commercially and in the backyard orchards.

Well, my ‘backyard’ trees are pretty much full in on G.41, which isn’t listed as one of the issue rootstocks so if I run into your cracking issue I’ll post back here.

Sorry to hear about the losses.

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I certainly hope you do not have this issue with your G41. I was hoping the G series rootstocks were going to be my go-to rootstocks. If you run into any issues keep us posted. TY

Regarding my original post: I think that Geneva roots (minus any scion specific issues) are probably great for many acres of trees. If I was planting a high density orchard, I’d probably use them.

The issue I was pointing out with this thread was that there is a potential in the genetics of Geneva roots for virus susceptibility. The trait in Ottawa 3 seems to be fairly heritable, and has been observed for some Geneva roots with that parent. I think that might be a real problem for us swapping scions and doing many-graft trees.

A secondary issue is that it may take many years for any evidence for/against virus susceptibility to prove out. And it might be that the industry and Profs. at Cornell don’t really care, because the passing around dirty scions isn’t something that is going to be a major issue in the industry. Lots of the ads from the big nurseries in GFG are for virus-certified scion material.


Sorry, I was lazy typing. Alkie is short for Alkmene. Not a common variety, but it sounded like an interesting one. I don’t have any Cox type apples, and this one has some of its ancestry. It was between this and a Kidd’s Orange Red in that regard. Like I mentioned earlier, it already has a bunch of little purple blooms on it, and it hasn’t been in the ground a month yet.

G30 has a bit of an issue with the graft union snapping with certain varieties, and I have three trees on it. But, I’m not too worried about it, we’ll just have to wait and see. My G30 trees are Roxbury Russet, Zestar and Suncrisp.

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I’ve heard of that variety, Alkmene. Sounds like an interesting apple to try out. A sort of early September tart like apple. Keep us up dated when you actually get some fruit to taste. May be a variety worth adding to my orchard. Thank you for the update on the name.

I meant to add that Rubinette was the other Cox type apple I considered. But, it has more disease suspectability than the other two varieties. Folks on here have had success with Rubinette, but I just wanted something a bit more easier to grow.

Never tasted any of these apples, so it’s a bit of a risk, but we’ll see. I’ve planted a few varieties that I’ve never tried before, I got them mostly based on write-ups and reviews on them- Novaspy, Pristine, Macoun, King David. Hopefully they’ll be good apples for us.

Alkmene is pretty good, sharp and highly aromatic Cox-like. It doesn’t store too long though. Here in IA I think it is more of a mid to late August apple.

I have had them the last couple of years from a local orchard CSA share. They might keep a month in the fridge if you are lucky.

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