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Pea gene 'n'

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  • Pea gene 'n'

    Reading Templeton's blog (entry of 2 June 2015)
    about the 'n' gene in peas, informs us that this gene is pleiotropic - which means that it has further effects than just thickening the pod wall of a pea - it changes a mangetout into a snap pea, but that change comes with other changes that cannot be separated from the change to thick pod walls.
    There is literature quoted on the JIC Pgenes pages
    and I read this article:
    The conclusion about all the changes are summarised here:

    "The major effect of the n gene when homozygous recessive was to produce plants with curved pea pods, round in transverse section, having thick pod walls. The nn plants also had pods with less length, width, area, volume, and weight than pods of N_ plants."

    Recommendation for pea breeders:
    "…… breeders ……. may profit by selecting for both thick pod walls and greater pod weight."

    Several conclusions for my own breeding:

    Bang goes the idea of breeding a massively large snap pea

    The curve, which is so attractive in Charlie's Goldsnap, is not a fluke, but part and parcel of the 'n' gene. The supplementary question that arises out of this is, why are Sugarsnap peas not particularly curved? And why are Opal Creek, which were bred from Sugar Snap, sometimes curved and sometimes more straight. Sugar Magnolia is straight, and my Sugar Beth snaps are all straight.
    (2. 7. 2015)

    Lastly, the advice to breeders is for selection. I am pondering this though - rather than only selecting after a cross, how about selecting for the largest parent varieties and start off with those? I don't have much data yet, but do believe that Charlie's Goldensnap might be larger than Opal Creek and that would be due to CEG being larger than Goldensweet (the other parent for Opal Creek). I need to keep an eye on size in future generations and select for this.
    Last edited by Galina; 18-08-2015, 10:42.

  • #2
    I have a few late pods of Sugar Snap and Sugar Magnolia and taken a photo. Neither are particularly curved. Maybe the connection between curved pods and 'n' isn't always the case?


    • #3

      Thanks for the extra info, Galina. Thinking on the run, starting with the biggest podded parents makes good sense. It might not result in bigger pods in the offspring if both the parents are using the same gene to generate big pods, but if there are different genes generating the big pods, then you might get additive effects, with even larger pods in the offspring. worth a try. I reckon that there is probably a lot of useful genes that haven't been properly explored in the literature, and that not every cross and combination has been tried. So let's go for it.


      • #4
        I don't think my Sugar Magnolia's were curved either? I've some growing, I'll take some pictures if and when they get to having pods!

        Sugar Magnolia from last year, these were from the hyper tendril type.

        Click image for larger version

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        • #5
          My snap crosses are in but not yet flowering - I'll keep an eye on them.


          • #6
            Oh for big fat tasty snaps!