Do 3-Way Crosses Exist?

[EBHarvey]

Awesome :clap:

Really, fantastic explanation. Thank you so much!

[ChrisK]

Here is a nice description, with pretty pix, of the stripe genes. Several of my F1's with gs show faint striping in the heterozygous Gs/gs combination, but not in all, as mentioned in the article below.

http://frogsleapfarm.blogspot.com/20...tripes-in.html

[Darren Abbey]

Cool article! It makes me really curious to see what comes from the seeds of the striped putative cross that turned up in my garden.

[travis]

Here is an example of the GS/gs skin striping in the F1 fruit.

[Darren Abbey]

Nice.

The striping on mine is much more intense, which is making me question its provenance.

I've got two more plants from the same seed that are still developing. They should tell me if I'm dealing with a random hybrid seed or a mix of segregations from a hybridization the previous year.

[EBHarvey]

The striping on mine is identical to what travis posted.....just apparent enough that it caught my attention among the dozens of red-ish F1s growing all around it.

One last question....Darren, one of the F2 segregants you predict is a yellow and tangerine. Is that likely/possible to be a tangerine fruit with yellow striping? I'd be willing to grow out a ton of this one if there was a good chance of that - sounds like it could be a beautiful tomato.

[GunnarSK]

Originally Posted by EBHarvey

Darren, one of the F2 segregants you predict is a yellow and tangerine. Is that likely/possible to be a tangerine fruit with yellow striping? I'd be willing to grow out a ton of this one if there was a good chance of that - sounds like it could be a beautiful tomato.

I hope we'll all hear more of this.

[Darren Abbey]

Originally Posted by EBHarvey

One last question....Darren, one of the F2 segregants you predict is a yellow and tangerine. Is that likely/possible to be a tangerine fruit with yellow striping? I'd be willing to grow out a ton of this one if there was a good chance of that - sounds like it could be a beautiful tomato.

That prediction is for a specific model of the genetics found in the parents. I don't have any idea of how the 'yellow' and 'tangerine' traits would interact. I also have no idea of the genetic interactions responsible for the stripe color.

Tangerine with yellow stripes would be a cool combination, however. My strategy would be to save a bunch of seeds from the F1 (from several fruit) and see how the distribution of F2s turn out in the coming years.
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With mine, it is looking to make less sense as an F1 the more I think about it. It has strong stripes (Gs/Gs) and is a beefsteak type (f/f), when the F1 would be expected to be (Gs/gs; F/f). I'm still planning to save a bunch of seeds and see how they look in coming years.

[EBHarvey]

Originally Posted by Darren Abbey

That prediction is for a specific model of the genetics found in the parents. I don't have any idea of how the 'yellow' and 'tangerine' traits would interact. I also have no idea of the genetic interactions responsible for the stripe color.

Tangerine with yellow stripes would be a cool combination, however. My strategy would be to save a bunch of seeds from the F1 (from several fruit) and see how the distribution of F2s turn out in the coming years.
----

Well, I got my wish.....this year about a half dozen plants decended from that 2013 selection did produce tangerine colored fruit with yellow striping. The F2 they came from had yellow striping on a red background and the F3s are about half yellow on tangerine and half yellow on red. The tangerine ones are really beautiful but, unfortunately, I haven't tasted one yet that's even decently-flavored. Will save seeds regardless for the genetics.

[travis]

In simple English, is it possible for t/t x r/r to throw an R/r plant? Yes [ ] No [ ]

If not, is it possible that either or both Y. Brandywine and G. Zebra carry beta carotene genetics along with whatever lycopene genetics sufficient to throw what actually may be that red orange fruit typical of an F1 result of R/r x beta carotene parent? (The color one sees when Rutgers x Caro Red for example.) And the viewer may optically process the color as simply "red?"

[maf]

Originally Posted by travis

In simple English, is it possible for t/t x r/r to throw an R/r plant? Yes [ ] No [ ]

If the t/t parent is also R/R at the yellow flesh locus then yes.

More generally I have not grown Yellow Brandywine but it appears from a quick research to be orange and not yellow. Going back to the first post of this thread "it was supposed to be a yellow brandywine X green zebra cross but it is red with delicate yellow striping, similar to beauty king but not as pronounced." that is exactly what I would expect in the F1 from a plant that was R/R, t/t, GF/GF x one that was r/r, T/T, gf/gf.

Also, there is some mis-information about the behaviour of gf on the first page of this thread. (I would like to point out that this wrong info was not from you Travis). Without going back to tackle everything (who has the time?) I will quickly say this:
gf/gf in an r/r background = green flesh color
gf/gf in an R/R background = dark flesh color (ie maroon, brown, purple...)

[EBHarvey]

you two lost me at "in simple english..." : )

[travis]

Sorry, I was responding to this older post, which I have trouble wading thru:

Originally Posted by Darren Abbey

[my initial model.]
YB : r/r;T/T;Gf/Gf ('yellow' color.)
GZ : R/R;T/T;gf/gF (green color.)
F1 : R/r;T/T;Gf/gf (red color.)

[Travis's model.]
YB : R/R;t/t;Gf/Gf ('tangerine' color).
GZ : r/r;T/T;gf/gf (green color).
F1 : R/r;T/t;Gf/gf (red color).

You're right, there are multiple models which are consistent with the observed F1.
As long as you have a geneticist's intuition, you're doing alright.
----

So, lets dive in a bit deeper and examine the possibilities.

The models which would produce the yellow/tangerine color in YB and green in GZ, while ignoring the stripes, are...
YB : (R/R;t/t;Gf/Gf) or (r/r;t/t;Gf/Gf) or (r/r;T/T;Gf/Gf) => yellow or tangerine.
GZ : (r/r;t/t;gf/gf) or (R/R;t/t;gf/gf) or (r/r;T/T;gf/gf) or (R/R;T/T;gf/gf) => green.

So, we can examine what all 12 possible crosses for these models would produce as an F1...
Each line shows a possible genetic model for YB crossed to a possible genetic model for GZ.
Any combinations which predicts a red F1 are bolded.
1) YB x GZ = (R/R;t/t;Gf/Gf) x (r/r;t/t;gf/gf) => (R/r;t/t;Gf/gf) (tangerine color.)
2) YB x GZ = (R/R;t/t;Gf/Gf) x (R/R;t/t;gf/gf) => (R/R;t/t;Gf/gf) (tangerine color.)
3) YB x GZ = (R/R;t/t;Gf/Gf) x (r/r;T/T;gf/gf) => (R/r;T/t;Gf/gf) (red color.) (Travis's model.)
4) YB x GZ = (R/R;t/t;Gf/Gf) x (R/R;T/T;gf/gf) => (R/R;T/t;Gf/gf) (red color.)
5) YB x GZ = (r/r;t/t;Gf/Gf) x (r/r;t/t;gf/gf) => (r/r;t/t;Gf/gf) (yellow/tangerine color.)
6) YB x GZ = (r/r;t/t;Gf/Gf) x (R/R;t/t;gf/gf) => (R/r;t/t;Gf/gf) (tangerine color.)
7) YB x GZ = (r/r;t/t;Gf/Gf) x (r/r;T/T;gf/gf) => (r/r;T/t;Gf/gf) (yellow color.)
8) YB x GZ = (r/r;t/t;Gf/Gf) x (R/R;T/T;gf/gf) => (R/r;T/t;Gf/gf) (red color.)
9) YB x GZ = (r/r;T/T;Gf/Gf) x (r/r;t/t;gf/gf) => (r/r;T/t;Gf/gf) (yellow color.)
10) YB x GZ = (r/r;T/T;Gf/Gf) x (R/R;t/t;gf/gf) => (R/r;T/t;Gf/gf) (red color.)
11) YB x GZ = (r/r;T/T;Gf/Gf) x (r/r;T/T;gf/gf) => (r/r;T/T;Gf/gf) (yellow color.)
12) YB x GZ = (r/r;T/T;Gf/Gf) x (R/R;T/T;gf/gf) => (R/r;T/T;Gf/gf) (red color.) (my first model.)

The F1 hybrid for half of the possible model crosses match what was observed. Discriminating between the models would require looking at the distribution of traits in the F2 progeny.

Predictions for F2 progeny sets per model cross...
#3,8,10) 16/64 green; 27/64 red; 9/64 yellow; 9/64 tangerine; 3/64 yellow&tangerine.
#12) 16/64 green; 36/64 red; 12/64 yellow.
#4) 16/64 green; 36/64 red; 12/64 tangerine.

If you combine 'yellow' & 'tangerine' into 'yellowish'...
#3,8,10) 16/64 green; 27/64 red; 21/64 yellowish.
#4,12) 16/64 green; 36/64 red; 12/64 yellowish.

You'd need to grow out quite a few plants (for the size of my garden) to confidently observe the difference between 12/64 and 21/64 in the F2 plants, and then you'd still have alternate models that would be consistent with the data collected.

[bower]

Originally Posted by travis

In simple English, is it possible for t/t x r/r to throw an R/r plant? Yes [ ] No [ ]

If not, is it possible that either or both Y. Brandywine and G. Zebra carry beta carotene genetics along with whatever lycopene genetics sufficient to throw what actually may be that red orange fruit typical of an F1 result of R/r x beta carotene parent? (The color one sees when Rutgers x Caro Red for example.) And the viewer may optically process the color as simply "red?"

This year I'm growing both tangerine and Beta orange plants, and I think I have figured how to tell them apart with clarity.
This I have pried out of the literature:

tangerine is only expressed when homozygous tt. so no partial expression in Tt, the fruit will look red or yellow as the case may be for RR, Rr, rr.
Beta is expressed in both BB and Bb. Bb fruit turns bright orange first, then slowly acquires red hue to the 'orange-red' condition. So regardless if the colour is processed as 'red', the fruit was certainly very orange on its way to the final colour, as I've seen in my F1's and F2's, and there is no yellow stage in the ripening colours..

Beta is only expressed if RR is present. Not expressed in Rr nor rr plants, if I read correctly.
tangerine if tt is expressed in both RR and rr fruit. probably in Rr fruit too. This produces "orange" (RR) and "yellow-orange" (rr) fruit.
So the question, could Beta genetics be lurking in Yellow Brandywine and Green Zebra... yes it could, because it would not be expressed at all in the rr condition. It would be completely suppressed though, and wouldn't be contributing to a 'yellow-orange' colour in YB.
It would not be expressed in the F1 X either, because it needs RR (I don't think even Rr will allow it to express).

Another, easier way to identify tangerine vs Beta genetics is flower colour: The tangerine gene suffuses the anthers of the flower with orange colour. The Beta gene does not, looks just like a flower of a red fruited tomato, with deep yellow anthers that turn orange as they age. Just look at the anther colour when the flower first opens... if it is already a deep orange, it's tt tangerine.

This year I have three 'tangerine' OP's with the deep orange anthers, that ripened fruit to date. Bursztyn is one that ripens yellow first then darkens to orange-yellow, so I think tt rr. Yellow Clusters and Datlo both ripen light orange to darker orange, so I think tt RR.

Incidentally, I checked the Sungold flowers in my friends greenhouse, and they are not 'tangerine' type.