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Old January 11, 2018   #24
BigVanVader's Avatar
Join Date: Mar 2014
Location: Greenville, South Carolina
Posts: 3,049

Originally Posted by bower View Post
Cool! I've been meaning to grow that one myself... You could get some really interesting fruit, and they'll all be determinates from the F1 onward.
I'm not sure at all about the genetics of bicolor - not much is written about it, and I haven't done any bicolor crosses so no observations to report.. KarenO could tell us something about the ratios that she got.
In any case, it is independent of the gf (black fruit).
So just to answer about your backcross plan, at least for the simple recessive black fruit gf,
JL bi F? (-/-) X Rodney F4 (gf/gf) - the F1 will be (gf/-) so not black.
(Since the parents aren't stable, you can expect variation in the F1, so I would advise to grow several and take F2 seeds from the best. )
JLbiR F1 gf/- X Rodney F5 gf/gf would give you 1/2 black offspring
while the growout of JLbiR F2, the odds of gf/gf are 1/4.
(You also have the same odds of (-/-) in the F2, that is, no gf allele 1/4. And 2/4 will be gf/- so although not black the allele is still there. If you backcrossed the F2 to Rodney F6 randomly in this generation, the odds of black fruit would be 3/4).
So you don't need to wait til F2 to increase the odds of black fruit and flavor genes from Rodney if you want to do that. You could also cross back to Rodney after you ID the black fruit in F2 if you want to, for 100% black fruited with variance in the other traits.

Traits like taste, cold tolerance, earliness are complex and they are additive involving multiple QTL's (many genes involved). What is really cool is that you can get unique flavors emerging from combination of parents, also earliness and cold tolerance combinations that are an improvement on either of the parents.
That is not even to mention the 'tricolor' effects from crossing black and bicolor.
So the main thing really is to play along with what nature provides you to select from. If you have the chance to do some backcrosses, do them and stash away the seeds, is my attitude. You may decide you want to use it somewhere down the line.

I will be interested to hear, whether Joseph's bicolor is earlier and more cold tolerant than Rodney. There is room for improvement, always!
Wow bower thanks so much. This is going to be very interesting!
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