[quote=TZ-OH6;97996]In my germinations this spring I had one Anna Russian pop out potato-leaf, and one Red Brandywine-potatoleaf, pop out regular leaf. I quickly sowed another dozen seeds of each to see if the packs had mixed seeds or crossed seeds in them. So far only those single plants have come up 'off-type'. There is no chance that a seed mix-up happend on my end.
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Red Brandywine should be RL. The PL Brandywine that you have isn't Red Brandywine and some PL RB's are listed at several places. Perhaps you got yours from TGS.
Are these two varieties ones that you bought seed commercially?
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Can I reasonably assume a leaf mutation [vs. a foreign seed] if the Anna Russian-PL come out heart-shaped?
That's a dicey question. There's more than one kind of mutation that can occur and if it were a spontaneous mutation affecting just the leaf form gene that might be true, but some mutations can affect other changes in addition to leaf form.
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The Red-Brandy-RL would have to have identical fruit to the potatoleafs to be a mutation. I have a handful of other red RLs to compare it to for variation. Whatever that Brandywine turns out to be it won't be a real red Brandywine, since the potatoleaf parentage is a mystery. But, maybe I'll get a Pseudo Earl's Faux ;-)
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What you have now, the PL RB, is a faux RB, as I mentioned above. So if you get an RL it's going to be a faux RL RB.
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How often do you all [Y'all, yous-guys] find foreign seeds in your seed packs?
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Again were these purchased seeds, or trades b'c it can make a difference in terms of seed purity and it makes a difference in terms of which companies you buy from as well.