Quote:
Originally Posted by TZ-OH6
How can a potatoleaf be genetically unstable for leaf type? It is a homozygous recessive trait. The fruit characteristics would be all over the place if the variety were unstable, but not the leaf type.
|
Good question.
Black Brandywine is not the only variety that shows instability with a PL leaf form. If self pollenization were complete one wouldn't expect to find RL forms from saved seed.
I'm trying very hard to remember the variety I once grew that was supposed to be PL, and sometimes was, but when I'd save seed from the PL I'd get back both PL and RL plants and when I saved seed from the RL the same thing would happen. But the fruit form remained the same.
With BB it isn't only the leaf form that's genetically unstable, but also the fruit form as many folks have noted and Camo also noted above.
How this is happening at the molecular level I don't know so I have no good answer for you. All I know is that it happens.
I'm thinking of the variety Lutescent, which is stable, but the pale foliage, pale blossoms and fruit maturation sequence re color from green to white to yellow to orange to red is not common and it's been theorized that the variety arose by the mutation of a pleitropic gene, that is, one that controls several other traits.
So I guess what I'm asking is if any pleiotropic genes might be at work when a variety flip flops between PL and RL and only leaf form is altered? It's at least one possibility. So are jumping genes, which tomatoes do have.