Crossing tomato noob question.

[BigVanVader]

Originally Posted by Fred Hempel

Yes, if you want a potato leaf hybrid, both parents need to be potato leaf.

No. With a hybrid approach, the ultimate goal is for an exceptional hybrid that you produce over and over.

The crosses are unique crosses between parents

For example, if you have 6 parents, the crosses you can make are --

1 X 2
1 X 3
1 X 4
1 X 5
1 X 6
2 X 3
2 X 4
2 X 5
2 X 6
3 X 4
3 X 5
3 X 6
4 X 5
4 X 6
5 X 6

15 total crosses (not 20)

Ok I see. Thanks Fred! You da man Think you could answer about 1k more questions today?

[BigVanVader]

I found this one at Tania's http://t.tatianastomatobase.com:88/wiki/Siniy Looks like it might be a good parent for a hybrid cross.

[bower]

Wow so many posts while I was muddling along trying to write one.
Important point Fred made, each time you backcross you're starting over at F1, so it will take another 7 generations to stability (more or less).

[BigVanVader]

Originally Posted by bower

Wow so many posts while I was muddling along trying to write one.
Important point Fred made, each time you backcross you're starting over at F1, so it will take another 7 generations to stability (more or less).

Yeah. I think as long as it was in the first or second generation it would be fine, but again I'm a total noob so I probably have no idea what I'm talking about. Very exciting stuff though, besides I'm sure we can find some Florida growers to help us speed up stabilizing. I'm looking at you Marsha

[bower]

Fred, I'd love to learn more about the trait stacking approach...
What do you do with your 15 F1's? Cross them with each other?

Oh I just re read your post... the exceptional hybrid is the point! Sorry.

[Fred Hempel]

The 15 would be evaluated as F1 hybrids. This is what we essentially do these days. However, we do sometimes grow out F2s from the best F1s (to create more true-breeding lines).

Originally Posted by bower

Fred, I'd love to learn more about the trait stacking approach...
What do you do with your 15 F1's? Cross them with each other?

Oh I just re read your post... the exceptional hybrid is the point! Sorry.

[bower]

Originally Posted by Fred Hempel

The 15 would be evaluated as F1 hybrids. This is what we essentially do these days. However, we do sometimes grow out F2s from the best F1s (to create more true-breeding lines).

Are we close to the release of some of your new hybrids?
Are you seeing lots of merit to the hybrid approach, re: combining traits in an F1 that you (maybe) couldn't easily accomplish in a stable OP?
I must admit I haven't been wowed by a lot of earliness heterosis, in my breeding experiments. It hasn't turned up frequently put it that way. Being a much touted example, I found that a bit disappointing.
OTOH I am having lots of musing about taste and other traits heterosis along the way.
Don't forget, none of my few crosses are even stable yet, so I am years away (or decades, ;or light years ) from coming to any kind of conclusions.

[Fred Hempel]

For stacking traits like disease resistance, shelf life and vigor (while retaining high flavor) we are finding that hybrids are a very good way to go. But we still do develop some interesting OP lines to release along the way too.

We are close to releasing 3 cherry tomatoes independently (at least at first). The 3 new hybrids are described here. They won't be generally available until this fall, but we will be allowing folks to sign up for the "rewards" described at the link, until March (if they really want to try the new hybrids this summer).

We are also taking another crack at finding a Red Bumblebee hybrid to release. So far we have evaluated 55 Red Bumblebee type hybrid crosses. We are closing in on just the right cross...

Originally Posted by bower

Are we close to the release of some of your new hybrids?
Are you seeing lots of merit to the hybrid approach, re: combining traits in an F1 that you (maybe) couldn't easily accomplish in a stable OP?
I must admit I haven't been wowed by a lot of earliness heterosis, in my breeding experiments. It hasn't turned up frequently put it that way. Being a much touted example, I found that a bit disappointing.
OTOH I am having lots of musing about taste and other traits heterosis along the way.
Don't forget, none of my few crosses are even stable yet, so I am years away (or decades, ;or light years ) from coming to any kind of conclusions.

[BigVanVader]

Originally Posted by bower

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!

[bower]

Originally Posted by Fred Hempel

For stacking traits like disease resistance, shelf life and vigor (while retaining high flavor) we are finding that hybrids are a very good way to go. But we still do develop some interesting OP lines to release along the way too.

We are close to releasing 3 cherry tomatoes independently (at least at first). The 3 new hybrids are described here. They won't be generally available until this fall, but we will be allowing folks to sign up for the "rewards" described at the link, until March (if they really want to try the new hybrids this summer).

We are also taking another crack at finding a Red Bumblebee hybrid to release. So far we have evaluated 55 Red Bumblebee type hybrid crosses. We are closing in on just the right cross...

They look great, Fred. Wow, 55 Red BBee crosses.... the amount of work is staggering!

[tpeltan]

Originally Posted by bower

Important point Fred made, each time you backcross you're starting over at F1, so it will take another 7 generations to stability (more or less).

With F1 parents. The stability of of the backcross should be similar to the stability of recurrent parent, but this parent can be stabilized during the backcrossing increasing the stability of backcrosses.

[bower]

hi tpeltan, welcome to T'ville.
Actually I saw your post in my inbox before you deleted it - and it made perfect sense. If you backcross to one of the parents, or to a sibling in the same line, you're still moving towards stability. indeed, more homozygous genes is bound to result.
It does get a little tricky to reckon, just when will it be completely stable. maybe seven generations is a good bet, whether you backcross or not. At least for us amateurs.

[tpeltan]

Originally Posted by bower

hi tpeltan, welcome to T'ville.
Actually I saw your post in my inbox before you deleted it - and it made perfect sense. If you backcross to one of the parents, or to a sibling in the same line, you're still moving towards stability. indeed, more homozygous genes is bound to result.
It does get a little tricky to reckon, just when will it be completely stable. maybe seven generations is a good bet, whether you backcross or not. At least for us amateurs.

Hello and thanks for welcome.

I read the previous part of thread in wrong direction and if I understand it now correctly they intend to backcross to unstable line. Then my post made little sense (despite being correct for stable lines).

The original post:

This is not true. If you backcross (to stable (OP)) variety = homozygous genotype, you increase the share of this variety. If you backcross the F1 to one of parents, the result will have half genes homozygous (equal to parent) and half heterozygous. This is comparable to F2 (where half remains heterozygous, half homozygous (quarter and quarter equal to each parent).

e.g.
BC1: F1 x P = Aa x aa = Aa + aa
BC2: BC1 x P = (Aa + aa) x aa = Aa + 3 aa

If you practice backcrossing long enough, you result with the parent you backcross to (and hence stable).

[jmsieglaff]

Hi Fred,

The Madera tomato is sure a nice looking tomato.

I reminded me of a tomato I grew in 2017, Garnet cherry. Have you ever grown Garnet? If so, how do the two compare?

We really liked Garnet in 2017--foliage health, extremely vigorous, very high production and excellent flavor and are growing it again in 2018.

Justin

[crmauch]

Originally Posted by BigVanVader

For example, how do you know what traits are recessive vs dominate? Also is there a good book that would be helpful?

The list someone already posted is good, but can be overwhelming as there are a tremendous number of 'genes' found, but most of them are minor or useless except for scientific study. Also note that a number of genes and there 'allelles' recessive forms used to be noted by capitalization for the dominate genes and lower case for the recessive and early genes were named for the their dominate type (like R for Red-flesh). I've notice that in some cases the way things are noted have changed. Now genes are usually named for the recessive form and the dominate form of the gene is noted with a plus symbol (+). So the gene that controls determinate growth versus indeterminate is labeled as sp (for self-pruning) and the dominate form of the gene (which is the indeterminate form) is sp+.

Two good books to start with:

"Breed Your Own Vegetable Varieties: The Gardener's and Farmer's Guide to Plant Breeding and Seed Saving", 2nd edition by Carol Deppe (although I liked the 1st edition better)

"Plant Breeding for the Home Gardener: How to Create Unique Vegetables and Flowers" by Joseph Tychonievich

Neither is solely about tomatoes.

Chris