(Opalka x My Brandywine) x Bianca Grande

[PaddyMc]

I don't have a name for this line yet. Opalka is a really nice paste tomato - low moisture, low seed count, rich flavor. Brandywine is all about the flavor, and my selection has great production and good fruit size. Bianca Grande is a cool white with great sweetness. Originally I was envisioning a very low moisture, low seed count, large size,  great tasting white. I was thinking white sauce with taste. And in the F2 I got a very big white beefsteak with great production.
Now at F3 I got no whites, but I don't care any more because I got some lovely, productive, tasty yellows and oranges!



7-1, 7-3, 7-4.  7-1 gets the nod going forward due to it's great taste and low seed count. It's a bit "oranger" then the pictures make it look.


7-2. Very subtly bicolor


K 7-3. The white-ish one.

[Darren Abbey]

Which F2s did you use to parent the F3s? I was under the impression the white trait was driven by recessive alleles, such that whites would be expected to recur in the F3 if they were selected in the F2.

[PaddyMc]

Originally Posted by Darren Abbey

Which F2s did you use to parent the F3s? I was under the impression the white trait was driven by recessive alleles, such that whites would be expected to recur in the F3 if they were selected in the F2.

I thought the same! I suspect that TRUE whites are double recessive (white/white) where as the F2 "white" from which these were grown was more of a very, very pale yellow (which most so-called "whites" really are). In which case it could have been (white/yellow) heterozygous with the "white" being expressed. And now at F3, we're seeing primarily heterozygous with yellow expressed or homozygous yellow (the orange fruit). For what it's worth the F2 looked like a bigger, slightly lighter colored version of the last picture.
I've also been at this tomato breeding game long enough to think that the "hard and fast" rules about gene dominance in tomatoes ain't so hard and fast! For instance, I've had lots of lines with either stripes or antho at F1, in crosses where those (supposedly recessive) traits shouldn't have shown up until F2.

[Darren Abbey]

Originally Posted by PaddyMc

I thought the same! I suspect that TRUE whites are double recessive (white/white) where as the F2 "white" from which these were grown was more of a very, very pale yellow (which most so-called "whites" really are). In which case it could have been (white/yellow) heterozygous with the "white" being expressed. And now at F3, we're seeing primarily heterozygous with yellow expressed or homozygous yellow (the orange fruit). For what it's worth the F2 looked like a bigger, slightly lighter colored version of the last picture.

I have yet to work with any crosses involving the "white" trait, though one is planned. From the reading I've done, it appeared that the "white" allele was simply a stronger suppression of the carotenoid pathway than is seen in the "yellow" allele. That you could have any two alleles of white, yellow, or red at the single locus.

What you've described sounds like it tells a different story. My impulse would be to grow out a lot more F2s and F3s (from the white) until I could understand what was going on… but I have a compulsive need to solve puzzles that you may not.

Originally Posted by PaddyMc

I've also been at this tomato breeding game long enough to think that the "hard and fast" rules about gene dominance in tomatoes ain't so hard and fast! For instance, I've had lots of lines with either stripes or antho at F1, in crosses where those (supposedly recessive) traits shouldn't have shown up until F2.

Definitely. I'm working with a batch of F2s that is revealing several significant (to the phenotypes I'm looking at) genes which show partial dominance and don't match to any genes I can find names for. In my notes, I've taken to simply numbering them (1, 2, etc.).

[PaddyMc]

Originally Posted by Darren Abbey

Definitely. I'm working with a batch of F2s that is revealing several significant (to the phenotypes I'm looking at) genes which show partial dominance and don't match to any genes I can find names for. In my notes, I've taken to simply numbering them (1, 2, etc.).

We'd love to see them!

[Darren Abbey]

Originally Posted by PaddyMc

We'd love to see them!

I wrote up a blog post about my thoughts and observations (http://the-biologist-is-in.blogspot....ue-tomato.html). I need to grow out more F2s to get a clearer idea of what is going on and for now I want to keep this my personal project.