First cross: what to expect

[swordy]

Hello dear friends,
Last summer I implemented my first cross. My idea was to pick two strong vines with different colors and characteristics and cross them.
I picked Orange Kentucky Beefsteak (which is strong vigorous and produces sweet big fruits) and crossed it with Cherokee Lime Stripes (which is also vigorous and very productive and produces very tasty fruits).
What should I expect in the F1? What color? In next generations I can have an orange bicolor with stripes? Is that posssible?
Thank you!
Stelios

[bower]

Hi Stelios!
That sounds like a fun cross alright. I'm not familiar with the parents but I'm guessing your F1 will be red, or possibly bicolor.
Red is a 'background' color in many different colored fruits, while most exotic colors don't show up in the F1 because they are mostly recessive. But yellow can also be a background to the interesting recessives.
Red and yellow (and bicolor) are an either/or situation - different alleles at the same locus. See the recent thread about ry bicolor genetics, where the dominance of bicolor over yellow was reported by Frosti's observation.
If Orange Kentucky Beefsteak is a dark orange, it is probably the recessive tt tangerine in a red background. (RR) and (tt)
But tangerine can also be expressed in a yellow background, this gives a lighter orange fruit. (rr) and (tt)
I don't know for sure if tangerine expresses in a ry bicolor background. But it might? So perhaps you will find one in F2 and beyond. If OKB is not a bicolor, then it has either R red or r yellow allele. The bicolor from CLS would be dominant in F1 if OKB contributed a yellow r allele.

If Orange Kentucky Beefsteak is a Beta orange, then the background allele must be red (RR), it doesn't express in yellow, and I don't believe so in bicolor as well. IDK if it would express itself in a R/ry background either.
But afaik, Beta orange is less common in American heirlooms than the tangerine. (Beta is fairly common in some Russian cv's).

Cherokee Lime Stripes I'm assuming a green-when-ripe? And you mentioned (ry/ry) bicolor.
The green flesh color is a recessive gf/gf. The stripes would be a separate gene, and IDK for sure if this is recessive.
Green flesh and stripes are independent of the other colors and so they can be combined with bicolor, tangerine orange, etc.

So I think it may be possible you could have an orange bicolor with stripes in F2 or beyond. That is, if the orange is tangerine tt.
But I think not if the orange is from Beta BB.

I hope you can post some pics as you take this down the line, and we'll learn something from your results.

[Pippin]

Based on the pictures in internet, I would guess that you have tangerine, bicolour, green flesh, green stripes and green shoulders. That could result 32 (?) different colour combinations in F2 and later. I am speculating here too as it is not completely clear which genes you have and how some of these combinations behave (as @Bower so well explains).

The ”green stripes” can actually be green or yellow depending on if the green flesh is expressed or not. The green shoulders also seem to enhance the expression of the stripes making them stronger. The green shoulder would also remain in the ripe fruit when combined with green flesh (which would be a new phenotype not expressed in either of your parents). The yellow stripes may be almost invisible in ripe fruit so people often prefer the stripes with green flesh (when the stripes are also green).

In next generations I can have an orange bicolor with stripes? Is that posssible?

Many people count the ”bicolour” as two colours, yellow and red (although it is only one recessive gene). When you have the green flesh there too, then you have a tricolour. I guess that the red from bicolour could express as darker orange with tangerine and the yellow from bicolour could express as lighter orange (or even yellow) with tangerine. But this is the unknown.

I have a similar tangerine x bicolour cross in F2 phase next summer. Hopefully, I can report some observations of this issue here too.

[swordy]

Thank you both @Pippin and @Bower for your answers. That was so infortmative. And challenging for me frim F2 and after to achieve my goal! I will definitely show results of this project here. And I will look here for results of other members of similar projects, like you mentioned @Pippin

[Doffer]

Because Cherokee Lime Stripes is green with red inside i think its homozygous for the dominant gene Gr Greenripe. So the F1 will be Green with red inside.

[bower]

@Doffer Green ripe is a mutant that doesn't ripen due to impaired response to ethylene. So in such a case, the entire fruit would be green and not red? The pictures of Cherokee Lime Stripes look like a normal gf ry combination to me, with red inside at full ripe.
https://www.jstor.org/stable/4629823
I'm just checking at TGRC to see if they have pictures of Green ripe pheno.
Edited to add: the search for Gr didn't have any images but the description is as you said:
Fruit flesh turns slowly to yellowish green, remains firm; resembles gf, except that center of fruit turns red.
So that is another interesting possibility.
The only difference from gf + ry would be that the fruit "remains firm".

[Pippin]

Agree with @Bower that Cherokee Lime Stripes looks like a gf ry combination.

Those non-ripening mutants are very different, see e.g. https://academic.oup.com/plphys/articl ... 67/6112818 where LA2453 is Gr and LA2455 is Nr-2 (also copying below for easier access). These tomatoes are rock hard at that stage because they don’t really ripen. gf+ry on the other hand ripens and gets soft but still remains green with red marks.

631A7136-19AD-43E3-A351-C1C7C7A6C7A9.jpeg

The Gr mutant was originally identified as a spontaneous mutant that retained chlorophyll in mature fruit (Kerr, 1958) and was subsequently described as a fruit ripening mutant (Jarret et al., 1984). The Nr-2 mutant was isolated as a spontaneous mutation in a breeding program and linkage to the long arm of chromosome 1 was demonstrated (Kerr, 1982a, 1982b). The C.M. Rick Tomato Genetics Resource Center (University of California at Davis) holds monogenic stocks of both mutants with the stock numbers LA2453 and LA2455 for Gr and Nr-2, respectively. The fruit phenotype at the ripe stage of development of these mutations is shown in Figure 1A

Edit: seems that I found exactly the same article than @Bower.

[swordy]

In the picture I post you see the unbelievable big production of the Cherokee Lime Stripes plants. Especially the plant father I took the pollen produced so many fruits. In the top right corner are the CLS fruits. While on the lower left one or two (the smaller ones) are Orange Kentucky Beefsteak. The mother plant wasn't equally productive. And the the fruit that was my cross was rather small compared to all the others I had picked earlier (it's not in this pic). I guess that won't be a problem since the genes come from the plant and not the specific fruit..

[bower]

Indeed, @swordy , you should get lots of variance in vigor and productivity, and you can select for the high production and high vigor in whatever interesting colors you get.
There are some vigor-associated traits which are passed down from the mother plant through mitochondrial and chloroplast DNA. I sometimes tried to use as a mother the parent with most outstanding physical traits (earliness, vigor, cold tolerance, disease resistance) but when I couldn't do that, I still got some very robust offspring using this as the pollen donor. So there is lots of nuclear DNA involved in those important traits, and doesn't matter which plant is mother or father. Productivity is complex for sure, involving everything from flower traits to cluster architecture and many more traits we could think of. So I expect you'll see a majority of vigorous and productive plants in your F2 with the additive traits from your CLS parent having a positive effect on most.
The hand crossed fruit is often smaller or larger than self pollinated fruit, and this gives you an idea of how important pollination is, to determine your yield. The smaller fruit probably shows that not as much pollination occurred this time as the average self pollinated fruit. Perhaps the pollen wasn't quite ripe at the time or the stigma wasn't exactly mature on the day pollinated. Sometimes I think I may have caused a bit of damage in the process, and the plant might decide not to invest (or not invest as much) in growing that particular fruit. Still the seeds you get are fine.