Hi Jack,
" I wonder what causes the change in number of leaves? I would not be surprised if it were an unstable genetic mutation... "
I am thinking genetics, and hopefully stable genetics. And if your Threesie also has 3Z side branches, as it apparently does, then you have a <u>very rare</u<> "pure" form. I have seen some 3Z stalks, and some 3Z branches, but never the two together in a completely 3Z plant.
The next hurdle is to get a lot of progeny from it. Some of its progeny may not get the 3Z genetics, but hopefully some of the selfed progeny will. It is very possible that more than one gene is involved, and all of them may be recessive. But that doesn't make it impossible to get a pure strain with all-threesie plants. More later.
ZM
