Hello,
You are pretty close. You make your cross and get your F1 (I assume they are both OP). You will need to self that to get to your F2. Now you have the decision to make now in the F2 if you want ot remake your parents or if you want to take any attributes from your 2 parents and me a new breeding line. After all you could always remake the parents and end up with 1 PL and 1 RL that are phenotypically the same as the parents. However they will differ genetically, sometimes quite a lot, unless you are doing marker breeding.
If you make the cross and do no selecting and just let self out you could get back to something like the website had. However if you are taking the time to cross this in the first place I assume you will be selecting w/in your populations.

Yuma

Thanks,
I guess it just surprised me that if you kept allowing self pollination, you would end up with two separate strains instead of one. I was trying to make an analogy to blue eyed and brown eyed humans and maybe it doesn't apply since people don't "self-pollinate". Haha...

The conclusion I drew is that if you were to cross, say a Hillbilly (PL) and a Black from Tula (RL), by the time you got to F8 and the genes segregated out, you would have two distinct varieties of your cross, one PL and one RL...Well from my simplistic approach, for a single indepedent trait it can be reduced to the following: (1-0.5)Fn-1. This is the probability that at generation F1 (F1=1), all of the crossed offspring will be hybrids, i.e., Rp or pR for this single leaf trait. So at F1, this is 100%. At F2, this resolves to 50%. And at F3 to 25%. This is assuming randomness and equal probability of survival for all. Now calculating 1/2 of the compliment of this value describes the respective population of the RR and pp phenotypes from such a mix at generation Fn where "n"= the generation. So at F2 it is 25% RR, 25% pp and 50% Rp (or pR). And at F3 it is 43.75% RR, 43.75% pp and 12.5% Rp (or pR). And so on. The "segregation" occurs because the RR and pp types cannot revert back to hybrids for leaf form, assuming self-pollination.

Reg

So how does a Rp or pR plant have RR offspring? I would think that if a plant self pollinates, it would produce offspring that are genetic clones. I must be missing something.

So how does a Rp or pR plant have RR offspring? I would think that if a plant self pollinates, it would produce offspring that are genetic clones. I must be missing something.The same way that type of cross for leaf trait can produce a pot (pp) leaf at F2. Even tho tom cults are self pollinating, they still do this in a male-female mode to make seed. So a genomic cross of an Rp "female" and an Rp "male" genome will produce tomatoes fruits seeds of which will have the combinations of: RR, Rp, pR, and pp for this leaf trait...at F2. That is 1/2 hybrid (Rp, pR, -- the genotype of the respective parents) and 1/2 homozygous (RR, pp) for this trait. This is the "segregation" here. And in this propagation scheme, the "hybrid" traits are much less likely to populate future generations.

This is why saving seed from hybrid tomato plants does not reliably replicate the parent plant. And so many more traits of interest are involved as well...

Reg

Thanks for your help, I think I am starting to get this. So is it possible for just one Rp tomato plant to produce Rp pR RR and pp offspring?

The simplest thing to recommend is an entry level class in genetics at your local 2 year college.

While Hillbilly is regular leaf, there is a version that is potato leaf. If you cross a potato leaf with a regular leaf, the hybrid will exhibit regular leaf characteristics, but it will be a bit wider than normal. I can usually tell a plant that carries both RL and PL genes at the stage where the plant has 3 sets of true leaves.

If you save seed from the F1 from a PL crossed with an RL, the offspring will segregate in a 1:2:1 ratio where one plant is potato leaf, two plants contain both regular and potato leaf, and one plant is a pure regular leaf. Since potato leaf is recessive, the potato leaf plants will always produce potato leaf offspring so long as they do not cross again. What you have to keep in mind is that you have a plant that is still segregating for other traits. This means that all the seedlings may be potato leaf, but some may produce red fruit and others bicolor fruit and interestingly enough, in some crosses, you may get yellow, and pink. Regardless of how many generations you grow, the potato leaf trait is "fixed" meaning that a seedling of a potato leaf plant will always be potato leaf, UNLESS it crosses with a regular leaf plant.

DarJones

So is it possible for just one Rp tomato plant to produce Rp pR RR and pp offspring?Yes that is correct (and I am no expert here). The Rp is a hybrid for leaf form, in this example. And so the seeds from its fruits will populate the leaf form in the manner of Rp pR RR and pp. So you can observe that upon the next generation, the leaf form trait will have a probability of: Rp RR pR pp : pp pR Rp RR : RR RR RR RR : pp pp pp pp which tranlates into 16 possibilities at this stage. So here you have 4 hybrids for leaf form (Rp pR pR Rp) and the rest (16-4) are homozygous for leaf form... equally divided on RR and pp leaf type. (4 hybrid + [ 16-4 ]/2 (RR) + [ 16-4 ]/2 (pp) = 16). So the "segregation" thusly happens.

Reg