Rootstocks: Do they impact flavor?

Earlier this year, as I was doing some research on the effects of grafting apple varieties to Malus angustifolia (southern crabapple), I kept running across interesting accounts of noticeable changes to the apple varieties when grafted to crabapples. One of these changes is in flavor, which is what I’m writing about today.

This is the original snippet that sparked my interest. Why? Because this dude back in the 1800s is telling me that when he took the Bethlehemite apple, a dessert/culinary apple from Ohio, and grafted it to a crabapple rootstock, he got something different from the original variety. The grafted Bethlehemite apple had developed some astringency. Astringency is the key word here.

OMG, DID THIS GUY TURN A DESSERT APPLE INTO A CIDER APPLE BY GRAFTING IT ONTO A CRAB ROOTSTOCK?

This thought has rumbled around in my head for the better part of this year and whenever I had a moment to sit at the computer and not read my emails, I researched this topic a bit more. First, I went back in history (via google books) to find more testimonials of these findings. Here are a few:

1867:

1871:

1873:

1889:

 

I could go on, but there are many, many testimonials in favor of rootstock having a flavorful impact on the grafted variety. There were some naysayers, who basically just said “this can’t be so” and changed the subject. But all in all, my historical research has been in favor of a rootstock’s ability to change flavor in apple varieties.

Eager to pursue this topic, I started looking up scientific papers on the subject and started with this, Cornell’s research on nutrient uptake by different rootstocks.  The thoughts and questions of the horticulturalists back in the 1800s seem to still align with the questions of today, as seen in this conclusion:

screen-shot-2016-12-04-at-7-57-50-pm

“The ability to match the nutritional requirements of a scion cultivar to a specially tuned rootstock…” COULD, in my opinion, create a cider apple out of a friggin’ dessert fruit.

Positive, I kept up the research and found considerable evidence in citrus fruit that rootstocks can change the flavor of the fruit. Here. Here. And Here.

This study, which looked at an apple rootstock’s impact on triterpene (cancer and immune disease prevention chemical compounds) found this:

“The largest differences in triterpene content were found between rootstocks. The results showed that both at harvest time, and after cold storage except the first harvest time samples, the apples from rootstock MM106 had significantly higher triterpene content compared with those from M9; … Selecting suitable rootstock might increase the triterpene content in apple peel in practice production.”

And this study on different rootstock’s impact on peaches showed that the variety ‘Suncrest’ on Julior (rootstock) and GF677 (rootstock), followed by Ishtara (rootstock), produced fruit with the greatest antioxidant activities and total phenolic contents. The ‘Suncrest’ on Citation (rootstock) and, especially, Barrier1 (rootstock) had reduced nutritional values of the fruit.

WHAT DOES THIS ALL MEAN? 

Right now, everyone I know who is planting a cider orchard is planting on known rootstocks like the MM series or the Geneva $eries. With these rootstocks, we know what size of tree we’ll get and we generally know when it will start cropping apples. This is valuable information because we want order and sense in our orchards. We also know the disease tolerances of each rootstock, which have been known to convey some resistance to the apple scion, and that’s all well and good. There are many knowns of these rootstocks because they’ve been extensively studied…for dessert fruit. But what about cider fruit? How many rootstocks have been thrown out in university trials for imparting astringency to an apple? Probably a lot. But what if this is what we’re after?!

If someone came to my farm peddling their wares and told me that they could take my dessert apple and turn it into a cider apple with one of their amazing magical rootstocks, I would buy it. I’m sure it would be a hit. This is why we have started in on the private research of grafting apple varieties to different rootstocks for the purpose of flavor/nutrient evaluation (as well as growth influences, which is another blog entry).

Currently, my partner and I have Malus angustifolia (southern crab), Malus baccata (Siberian crab), own-root, M7 and M111 trees grafted in our nursery to the same variety. These will soon get planted out at the farm in an area set up for evaluation. This, I believe, is another untouched frontier whose findings could be incredible for the future of growing superfruits, having value-added rootstocks, and growing with lower inputs.

So far, the science and the observations are there. There’s much more to learn, but why not start in on the fun?

 

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11 thoughts on “Rootstocks: Do they impact flavor?

  1. Great Thoughts and I believe it makes perfect sense. Interesting to note, in the New England, where I am, seedlings of Hewe’s Virginia Crab was known to be used as rootstock before the modern era.

  2. Makes me think grafting Golden Harvey to Dabinett own-rooted would be so worth the trial. In case you do not already know, Golden Harvey is a highly flavored and sugared apple from the UK, circa 1600. and is still used to produce cider, as well as big tasting (but small fruits) fresh eating. Dabinett is a small vigor tree and its fruit has a high tannin component. Would the Dabinett influence Golden Harvey over time?
    Hmm, where can I try this? Maybe you can before I manage to find a spot.

      • No, sadly. I have read about Golden Harvey and tried twice to graft it – without success so far. There isn’t a Golden Harvey growing in Washington state to my knowledge. It is possible someone on the Seattle side has it, but I have no knowledge of it.
        Perhaps I will order a bench graft from Greenmantle this winter. Two trees on this lot came that way years ago. They were English apples that later proved they cannot handle dry Spokane summers. GH might fall in that category, but Sturmer Pippin and Bardsey come through like champions, so I live in hope.
        I wonder how GH compares with Karmijn de Sonnaville? I got a few of those grown right by the Columbia River and they had flavor that grabs you by the tonsils and doesn’t let go! KdS is another that is reputed to need some humidity to yield well, so I won’t even try growing it here. Golden Harvey looks like it’s worth trying until I know for sure.
        Do you know how I could taste one?

  3. Super cool, gold star for great research! We are kindred spirits. When I want to know something relevant to subsistence activities and farming and such I usually think first to look at the 19th century. People were more curious and observant it seems and not as caught up in the dogma that is modern science. I’m also all about people experimenting instead of waiting around paralyzed into inactivity for someone like you or I to take the risks and prove the point for them. With this kind of thing a combination of widespread casual experimentation and more controlled scientific trials will give us more insight than either one alone I think, but if I were to choose one it would probably be the former because it will be in real life scenarios under diverse conditions.

    • Yes Steven, and although I have not room to try the same cultivar on several differing root stocks in order to assess which will effect flavor and such, I am trying cultivars here that no one else is trying in this area. A casual experimenter I am, although my wife would say I am hardly casual about it. This sort of thing occupies much of my free time
      Since I live in the North (Spokane, relatively mild for this latitude,) I wonder if anyone has noticed differences in the same cultivar when grafted to Antonovka, Bud118 and Duchess of Oldenburg? All three do fine in colder climes than my own and promote similar vigor.

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