My unscientific approach is simpler. with the heart crosses that seem to be stabilizing quickly, I used two known stable varieties and crossed them. Picked only 3 of the best F2's and brought them forward selecting as close to identical offspring from a F3 grow-out of only 6 plants each. I chose only 3 because that was all I figured I could deal with in the space I have. I did keep seed from a lot of the other F2's because they were all quite good, a few unbelievably good beefsteaks but I chose to only do the hearts because they are my favourite and there are so few PL hearts.
In my PL cherry project, I thought I was crossing 2 stable varieties again. Wrong. Turns out the cherry I crossed was unstable and the progeny continue to toss off oddities in F4 but that is from an oddity that turned up in the F3... so really it was still an F3 according to my simplified logic... meanwhile the 2 origional selections, one a dark green shouldered purple and the bright pink cherry I origionally selected are looking good going into F4 and only a small number of plants of each have been planted. By F3, according to the probabilities 75% should be looking the same but that is only if both parents are perfectly stable... Add in 2 unstable parents and the number of plants or even the total numbers of grow-outs I'm not sure can even be calculated for certain.
I hope the real genetics wizards can help you, clearly that I am not and my experience is limited to my own little projects but these are my thoughts and observations. I am working with a lot of recessive characteristics and so it is easier to see the differences and once the recessive trait is expressed it is fixed which also makes it easier.
Karen
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