Tomato double cross hybrids

[StrongPlant]

Has anyone ever tried it? What were the results?

[WhippoorwillG]

As in crossing two F1's?

If so, then yes. The only time I've done it was using two F1's I had created and wanted to see how they recombined with regards to vigor and fruit size.

There will be segregation in the initial hybrid from the hertero traits, but the extent will depend heavily upon the initial parents and their genetic "distance" from each other. Wild lines combined with more domestic varieties result in tons of possibilities. Combine two wildxdomestic F1's with different backgrounds, and you will have a YUGE amount of variability and a long road ahead. There will usually be a few dominant traits that are obvious with a lot of variability in the expression of other traits.

More experienced breeders can give better advice on the matter, but a double cross of this nature has shown limited use for me other than curiosity. I have much more luck working lines to F3 or F4 and then combining them based upon desired outcomes. This allows a more predictable outcome, but keeps the variability in play.

[StrongPlant]

Originally Posted by WhippoorwillG

As in crossing two F1's?

If so, then yes. The only time I've done it was using two F1's I had created and wanted to see how they recombined with regards to vigor and fruit size.

There will be segregation in the initial hybrid from the hertero traits, but the extent will depend heavily upon the initial parents and their genetic "distance" from each other. Wild lines combined with more domestic varieties result in tons of possibilities. Combine two wildxdomestic F1's with different backgrounds, and you will have a YUGE amount of variability and a long road ahead. There will usually be a few dominant traits that are obvious with a lot of variability in the expression of other traits.

More experienced breeders can give better advice on the matter, but a double cross of this nature has shown limited use for me other than curiosity. I have much more luck working lines to F3 or F4 and then combining them based upon desired outcomes. This allows a more predictable outcome, but keeps the variability in play.

I was wondering if it was worth it,as in will the F1xF1 be more more healthy/vigorous/productvive in comparison with single cross.I found some papers and it looks like single crosses are superior.I'm focusing mainly on F1's,I was just wondering about other possibilities,but I guess anything other than single cross and you're sacrificing uniformity among plants.

[bower]

Yes, the point of unstable crosses is that you will get diversity to select from, as much as possible.
There is also some merit in crossing F1 or F2 generations to maximize the chance of breaking linkages and getting unusual results iirc... There's a paper I was reading this spring... will check my notes and try to find it this evening.
I have to say that for me, my most interesting results have come from side crosses involving an F2 parent.

[PaddyMc]

Almost all of my most interesting segregates have come from complex crosses. Just know that you're committing to growing out a LOT of F1's, 2's and 3's if you want to get good results.

[StrongPlant]

Originally Posted by bower

Yes, the point of unstable crosses is that you will get diversity to select from, as much as possible.
There is also some merit in crossing F1 or F2 generations to maximize the chance of breaking linkages and getting unusual results iirc... There's a paper I was reading this spring... will check my notes and try to find it this evening.
I have to say that for me, my most interesting results have come from side crosses involving an F2 parent.

Genetic linkage is very interesting,I did not know however that crossing diverse genetic pools such as 2 F1's increases the chances of them separating.Huh,I learn something new almost every day.
Is was also wondering if there are any papers revealing which genes are linked to traits that are visually or otherwise identifiable without expensive tech.Things such as PL,sp(det.),fruit color,jointless etc. -this would be useful for any amateur breeder.

[bower]

Well I looked but didn't find it... either I lost or maybe I misinterpreted what I read. Yeah there is always something to learn. My grasp of genetics is shallow at best, but I keep reading and looking at my results to try and figure something out.
There are linkages between sp and Beta orange. This came up in discussion a couple of years ago as Crmauch was working on a Beta paste project and I also happened to be working on some Beta crosses at the same time too. You'll find if you cruise and read the forum.
I definitely didn't get mendelian results from my beta/sp crosses, but I did get some super sweet lines and luscious colors (not Beta colors) that seemed to come from nowhere.
This year I'm looking at another side cross I did, between the sp and Beta OP Orange-1 and the F1 of Napoli a Fiaschetto (det) X Black Cherry a few years ago. The point of the cross was to get 1/2 determinate. I got zero/4 determinates in a similar cross with Zolotoe Serdtse which is "semi-determinate", ", where I should have had 1/2 sp. It is certainly not as compact as Orange-1, and I wondered if the other genes in semi-det status played a role besides the linkage with beta issue (no beta in the 4 therefore no linked sp). I am growing out determinate F3's from that other cross, but I assume that both sp genes here came from Napoli a Fiaschetto, not from the Beta linked parent.
Then again 0/4 instead of 1/2 could be due to chance (!unlucky!). I have seven plants of the ORFI F1 this year and watching with interest to see what I get.