Interspecific commercial hybrid ?

[nicollas]

Do you know any commercial hybrid that is (presumably) an interspecific cross ? I've heard suppositions about Sungold but are there any other ?

thanks

[carolyn137]

Originally Posted by nicollas

Do you know any commercial hybrid that is (presumably) an interspecific cross ? I've heard suppositions about Sungold but are there any other ?

thanks

Most modern hybrids are developed by using two breeding lines and up to 4 parental inputs can be used in each line, so up to 8 parental inputstota.

The earlier hybrids such as Big boy, Better boy, Ramapo, etc., were bred using just two parents, both open pollinated so no individual genes used as would be true for the more modern hybrids.

To give just one example, as far as I know modern red cherries have a gene(s) from Solanum pimpinellifolium that codes for the flat truss seen with so many of them.

When volunteers of Sungold F1 come up those plants often are red fruited, and same when F2 seeds are saved from F1 fruits. I don't know how that happens b'c Sungold F1 does have the typical flat truss but in some way in the construction of the F1 hybrid the genes from S. Pimpinellifolium are suppressed so that the fruits are not red.

Perhaps someone with more genetic knowledge than me will come along and either confirm most of what I've said, add to it or disagree with some of what I've said.

Finally, there are genetic inputs for certain soilborne diseases that come from species as well, but just gene(s), not the entire genome as in one parent.

Carolyn

[travis]

Is the original question whether any commercial hybrids are comprised of one pure breeding line x one single species other than Solanum lycopersicum?

There are many modern hybrids that have Solanum pimpinellifolium in their pedigree, usually to capture certain disease resistances, but then the resulting outcross is subsequently backcrossed to the larger parent multiple times to attain the full sized breeding line.

There are folks who speculate Sun Gold as being a cherry breeding line x Solanum cheesmanaie, but in all the grow outs of F2, F3, etc. of Sun Gold and other Sun-sister lines, I have never seen anything that looks like cheesmanaie; so, I think it's a bit more complicated than that.

While some folks insist that modern hybrids can be comprised of "up to 8 parental inputs," I believe it's gone quite farther than that recently with hybrids like Tasti-Lee having umpteen parental inputs on each side of its pedigree brackets.

As to a specific commercial hybrid with a wild species as a singular and pure parental input, the resulting hybrid would surely be small, like a grape or cherry size fruit, since the F1 pretty much will be the square root of a x b in weight.

[nicollas]

Yes i was talking about pure wild parent, not introgression of wild genes. I guess this is not a common thing It is the case for rootstock but it is often said that the fruits of these F1 are green / not good / late ripening. Good point for the size too, if any exist, these interspecific commercial hybrid should be cherries.

[Fusion_power]

There are 3 possible parents that could be used in an interspecific cross and still yield edible fruit in the F1: S. Pimpinellifolium, S. Galapagense, and S. Cheesmaniae. S. Pimpinellifolium is widely considered to be the progenitor of the domestic tomato. Crosses with Pimpinellifolium are easily made, fully fertile, and can bring desirable genetics to the table. Unfortunately, Pimpinellifolium is small fruited which is a highly dominant trait. Crosses involving S. Galapagense and S. Cheesmaniae bring an increasing number of undesirable traits which limit potential to make domestic vs wild crosses that have production potential as F1's.

I have two crosses currently segregating in my garden. The most interesting is Piennolo del Vesuvio X LA0417 (S. Pimpinellifolium). I have segregation for foliage disease tolerance that is way beyond anything I've seen in any currently available domestic tomato. Of 16 plants grown out this year, 2 are highly resistant to septoria. One of the two is a slightly nippled oval fruit very similar to Piennolo, the other is a round 1 inch diameter fruit. The other plants in the group include 2 that were totally decimated by foliage disease and the rest that have varying levels of susceptibility. The nippled fruits from the disease tolerant plant are intriguing, they ripen with a glossy shine that I have not seen in a tomato before.

http://www.nature.com/ng/journal/v46...l/ng.3046.html

[travis]

Will seeds be available from the nippled fruits from the disease tolerant plant this year?

[Fusion_power]

I have seed fermenting now and will make some available for anyone interested in breeding. These plants are F2 so the seed will be F3. There will be a lot of segregation in the offspring.

[greenthumbomaha]

I thought I had a winner in both disease tolerance and productivity in my community garden 2 years ago. It was proudly standing undamaged in a garden of 70 diseased neighbors at the end of the season, and was also a red one incher. I grew two out this year and the productivity was great but starting early in the season both were a septoria magnet. Would be interested in possibly crossing yours with my remaining seed and give it another chance next year.

- Lisa

[NarnianGarden]

I have a question for those well versed in genetics. When the breeders make the final cross (let's say, for SunGold for example) to create the F1 seeds, how can they be sure that the breeding lines behave exactly like they're supposed to, with no surprises, no lottery?
yes I am sure they know their business and have calculated the risks and possible scenarios, but still.. nature is nature, and anything can happen. Unless it all happens in a lab setting...

[FredB]

Originally Posted by nicollas

Do you know any commercial hybrid that is (presumably) an interspecific cross ? I've heard suppositions about Sungold but are there any other ?

thanks

I believe that many of the supersweet cherry tomatoes such as Supersweet 100 Hybrid have S. pimpinellifolium as one of the parents. Apparently there is some sort of synergism between the genes for sugar production in the two species so that the F1 is sweeter than either parent. I've made some crosses with pimpinellifolium and seen that this is often (but not always) the case. One of my main projects is to try to stabilize the high sugar content in the F2, F3, etc. generations. I'm finding that it isn't easy but I haven't given up yet.

Responding to one of Carolyn's comments, I have also seen red-fruited plants show up in the F2 and later generations of Sungold. This means that one of the parents is a red tomato and the other is an orange tomato with the dominant B gene for orange color. See the link below from Frogsleap Farm for information on the genetics of tomato color.

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

The F2 and later generations of Sungold tend to be about the same size as Sungold, which makes me think it isn't a cross with pimpinellifolium, since you would expect a wider range of sizes if that were the case. However, there is definitely something exotic in its ancestry, and I wish I knew what it was.

Fred

Comment added later: On rereading the Frogsleap link, Del is another dominant gene for orange color. Del is partially dominant and B is more fully dominant. I'm not sure which of the two better fits the behavior of Sungold F2 and later generations. Some of the offspring are more yellowish than Sungold F1, which might come from being homozygous for Del.

[nicollas]

thanks Fred,

do you have some elements that makes you think that it is an interspecific cross rather than a cross with a tomato with introgressed gene(s) for enhanced sugar from the wild species ?

[carolyn137]

Fred posted:


Responding to one of Carolyn's comments, I have also seen red-fruited plants show up in the F2 and later generations of Sungold. This means that one of the parents is a red tomato and the other is an orange tomato with the dominant B gene for orange color. See the link below from Frogsleap Farm for information on the genetics of tomato color.


&&&&&&

No, it doesn't mean that one of the parents ( complete genome) is a red tomato, S . Pimpinellifoium has been used in the breeding of many cherry tomatoes since pimp has a geneS) for the flat truss type that is typical for so many cherries.

So in breeding Sungold F1, for sure they are breeding in just the gene(s)( associated with the flat truss) but also some associated pigment gene(s) that wentalong for the ride.

And Travis spoke topimp in an earlier post here as well.

So no, S pimp was never one parent with the complete genome being involved.

Carolyn

[NarnianGarden]

That's exactly what has been keeping me awake, Carolyn
You and others have repeatedly told me (and of course I believe you) that SunGold does not involve any genetic engineering, but is traditionally bred using several parental lines. Then, how can a single desired gene be segregated and bred into it, without sophisticated lab conditions?

[carolyn137]

Originally Posted by NarnianGarden

That's exactly what has been keeping me awake, Carolyn
You and others have repeatedly told me (and of course I believe you) that SunGold does not involve any genetic engineering, but is traditionally bred using several parental lines. Then, how can a single desired gene be segregated and bred into it, without sophisticated lab conditions?

The variety Rutgers is an excellent example and if you look at Tania's following page where you'll see SIX different Rutgers listed.

http://tatianastomatobase.com/w/inde...rom=R#mw-pages

And if you look at each one you'll see some are F, some FV, some FF and on and on.

No sophisticated lab conditions are needed at all.

Take an OP variety and say you want to introduce tolerance to Verticillium. You cross the variety with another variety, or one of the wild species that has that V gene.

Then you save seeds from that F1 and plant out many F2 plants, then you challenge each with the pathogen itself to assess the tolerances.

Very labor intensive, but that's how it's done.

And in constructing a modern F1 hybrid it's done the same way with two breeding lines and up to four gene inputs in each line for this and that such as high solids, uniform ripening gene, and yes, some disease tolerances as well.

Does that help?

Carolyn

[FredB]

Narnian -

Here is a link to an article describing how "Mountain Majesty Hybrid" was bred. It gets very complicated. In this case, about a dozen genes were combined by crossing, selecting for desired traits, making another cross, etc.

http://tomatoes.ces.ncsu.edu/wp-cont...011.pdf?fwd=no

For more information on tomato genes and breeding, try googling "Randy Gardner tomato", "TGRC tomato", or "Frogsleap Farm".

Fred