I always wondered that too good question, redisland_greenthumb

Same as any other hybrid, by manual crossing of the parent plants. Lots of hands-on labor and follow-up selection. When multiple parent stock is involved it gets even more complex.

Here is a link that might be useful: How are hybrid seeds produced?

Thanks for the replies, but this seed hybrid thing still isn't clear to me. If it were a case of vegetative propagation (selling Sungold cuttings) it would be easy . . . .

So Sungold is a product of two tomato parents, A and B. Cross A and B, get Sungold.

The way I envision it is the tomato gods are up there making all sorts of F1 crosses: Tomato A x Tomato B, Tomato B x Tomato C and so forth. One day, they cross Tomato A x Tomato Q and ONE of the resultant seeds, a genetic lottery winner if you will, grows up into Sungold.

Or is it that if you cross Tomato A x Tomato Q ALL the resultant seeds grow up into Sungolds? That seems unlikely to me :)

Or is the "Sungold F1" that we have in our seed package is NOT really an F1 at all? It's actually F10 or F11 that the tomato gods have selected out of all those self-crosses to produce, in essence, a tomato that reproduces itself when self-pollinated?

Help! I don't get it :)

The earliset hybrids such as Big Boy, Better Boy, Ramapo, etc, were selections made from the hybrid that resulted from crossing ONLY two OP parents.

That was then, but more modern hybrids are constructed using two different breeding lines, an A line and a B line, lets say, and in each of those lines there can be up to four parental inputs for different genes, so when the happy day comes when the last accession in A is crossed to the last accession in B then the F1 hybrid is formed.

Commercially the crossing of the last two in each of the breeding lines is done manually, I thought the link Dave gave explained all of this. but they can also use a male sterile where possible which saves work since then the male sexual parts don't have to be removed from the blossom and only the correct pollen is used.

You can save seeds from an F1, they're fine, but the liklihood of getting anything worth while is not high.

The Sungold F1 seeds you get in a package really are Sungold F1.

Some have tried to create OP versions of the F1 and the most successful of those have been the ones developed by Reinhard Kraft in Germany who has released in order:

Sungold Select
Sungold Select II
Big Sungold
Big Sungold Select, just released past year and perhaps the best to date.

Several folks have also made selections from a known named hybrid to try and get an OP version. I was successful doing that with Ramapo F1 and folks are now growing out F6 and F7's and it's remained perfectly genetically stable.

The seed business for hybrids is very competitive and that's why they don't say what the parental inputs to a hybrid are, except when you see certain tolerances for disease in a hybrid the origin of those are know to be from some of the wild species so that's known.

Have I helped with my post or do you still have some quetions?

Carolyn

Thanks everybody! Makes sense.

I had no idea it was so involved. I'm amazed. It's mind boggling to think the parent plants are so inbred as to generate the same result - Sungold - with every cross.

So, does this mean that the parentage of these hybrids is a jealously guarded corporate secret? Or it lack of access to the inbred strains that prevents home gardeners from producing their own Sungold?

parent plants are so inbred as to generate the same result - Sungold - with every cross.

Not "inbred", they are just stable open pollinated varieties perfectly capable of standing on their own and many of them have for years. Those of us who grow open-pollinated varieties in addition to hybrids actually gorw many of the parent stock varieties.

And Sungold doesn't necessarily result from every crossing as Carolyn said above. Selection, among the results, is part of the process and is how Reinhard Kraft has been able to develop the sub-set varieties of Sungold listed above.

jealously guarded corporate secret?

It is guarded research, copyrighted of course. Since so much work and money goes into developing one it wouldn't make sense for them to make the info readily available to all. Another reason why so many of us like to grow open-pollinated varieties. ;)

Dave

Just to clear up the last bit of confusion: crossing two completely stable parents (homozygous, for the geneticists out there) will result in every single offspring in that F1 generation having the same genetics. Since every seed gets one half of its chromosomes from parent A, and one half from parent Q, they all have a set of paired chromosomes AQ. Thus, every single F1 seed from those crosses grows the same plant: Sungold. It's not until they self-pollinate to make the F2 generation that the random assortment of traits asserts itself and you get a mix of plant types.

Things get really wacky when you're dealing with triploid/tetraploid veggies like bananas or potatoes, but thankfully, tomatoes are diploid (two matching chromosomes) just like us. :)

--Alison

Speaking of all the work and money it took to create Sungold, has anybody wondered why on earth Sungold isn't one of the the few hybrid cherry tomato varieties you find easily available as seedlings at big home stores and nurseries?

It is an amazing variety, and it is hard to believe that once a person bought some from Home Depot one year, that they wouldn't be hooked and want to buy it again next year. If I were an executive at Lowes or Home Depot, I'd be all over this.

Unless I'm wrong, and Sungold IS showing up in the big stores now, the best guess I have is that somebody's got the idea that people think that tomatoes are red, and that customers won't even try an orange tomato.

I don't know. I just think it is a gigantic mistake not to make Sungold available to the masses of people who don't start their own plants from seed. Of all the wonderful varieties I choose to start from seed over the seedlings available at stores, Sungold is number one on the list of ones that could and should be.

Sungold is readily available here in VT. I start my toms from seed so I know how they have been cared for from the start. (Besides bringing them on the market too early, box stores water sometimes and sometimes not and never feed.)

We have some very reputable nurseries that carry Sungold and the most popular hybrids along with a growing number of OPs/heirlooms because they are in such demand.

Check around your local nurseries/garden centers and you might be delightfully surprised to find they sell some of the tomatoes you are interested in. If you don't see it, especially this time of the season, ask if they have them in stock in the spring. If they don't carry them, ask if they will.

Thank you. I didn't actually throw that out there because I'd buy them (I start all of my tomatoes from seed, so I'd probably start my own even if I could buy seedlings.) I was just wondering why this fabulous variety hasn't become more available as seedlings.

I think my thought process was more along the lines of "Sungold is a hybrid, proably the best one I've ever tasted, so why on earth isn't it sold along side all of the other hybrids I see on the shelves at Lowes and Home Depot?"

There are strong regional influences on what varieties are carried locally - even at the nurseries much less the big box stores.

For example, one rarely finds ANY cherry varieties for sale as transplants in our neck of the woods. There is just no interest or demand for them. Even the local growers who sell plants at the farmer's markets don't offer any of them.

Believe it or not, there are lots of tomato grower/lovers who consider cherry varieties a waste of time and space and when it comes plant sale time they let us know that in no uncertain terms. ;)

Dave

I had no idea this is how tomato breeding worked
http://www.avrdc.org/LC/tomato/hybrid/01title.html (from the link above)

But it actually raises an interesting thought:
For the heirloom tomatoes to come true from seed, they (like the Sungold's inbred parent lines) must be entirely homozygous at every loci. Otherwise you would get variation in the progeny.

Which means that the heirlooms are stable because they're so inbred they've lost all extraneous genetic variability. Who would have thought that the Sungold F1 has more inherent genetic diversity than Brandywine?

But it actually raises an interesting thought:
For the heirloom tomatoes to come true from seed, they (like the Sungold's inbred parent lines) must be entirely homozygous at every loci. Otherwise you would get variation in the progeny.

****

True that OP's should be homozygous for all genes but despite that one can see biological diversity, genetically, within a specific variety b'c nothing is static in terms of seed germplasm. Those with eyes that can see can put out 10 plants of a specific variety and see subtle differences in leaf form, internode distances, etc.

(Which means that the heirlooms are stable because they're so inbred they've lost all extraneous genetic variability. Who would have thought that the Sungold F1 has more inherent genetic diversity than Brandywine?)

As I mentioned above OP's are not devoid of the capacity for genetic variability.

Since most of the many parental inputs into hybrids, Sungold F1 included, are single genes for some systemic disease tolerances, high solids content, the uniform ripening gene so there are no green shoulders, etc., that doesn't necessarily say that there's more genetic variability with Sungold F1 or ANY hybrid as I see it than there is in an heirloom variety.

it's been estimated that about 95% of the heirloom varieties arose by natural cross pollination and then someone making selections from that initial hybrid and stabilizing it out to a stable OP, so there's lots of genes in there from two other complete genomes that have sorted themselves out by gene segregation as the selection process goes forward.

The other 5% of heirlooms are said to come from mutation from existing varieties whether that be by Seed DNA mutations or more rarely by somatic DNA mutations within the DNA of a plant cell.

Carolyn

Who is the manufacturer of Sungold? I don't think it is Seminis, Sygenta or Nunhem but I cannot find who it is. I wish that stuff was transparent!

I finally found it. It is Tokita Seed.

I am skeptical of the method that commercially produce "F1" seed (mass production) . It is not obviously a "scientific" approach. So the logical scientific way would to be fast produce an stable product.

The other thing is just playing with the words. Example F1, F2 ,...Fn all are "HYBRIDS". At some Fx it might have already stabilized but the seeds company continues to sell it as "Hybrid". And the general public would not bother to save seeds from that "Fx".
It is hard to believe that, eg, Burpees is still producing and selling Big Boy F1.
Call me skeptic.

Seysonn

"I am skeptical of the method that commercially produce "F1" seed (mass production) ... Example F1, F2 ,...Fn all are "HYBRIDS".

In that sense, everything is a hybrid, because you are saying it is the result of the crossing of two parents and all presentations that develop from that cross down the line.

In the seed business, an F1 hybrid is formed by two parents that always give the same set of traits that define the hybrid seeds being sold. The set of traits expressed is called the desired phenotype.

F2, F3, ... Fn will have material from both of the original parents, so it is only a cross in that sense, but it will no longer be that dependable, uniform 50/50 combination giving solely the desired traits since F2 has scrambled the DNA after the second pollenation event on the grow out of your harvest.

Two uses for the word "hybrid".

1) Loose: A random simple cross resulting in diverse groups of F1's, better called a "cross" and not identified in industry with the label "F1" to avert confusion (even though it is), and generally results in a variety of segregating phenotypes.

2) Strict: A researched and developed cross from parents selected so that all desired traits are always expressed in F1's = uniform, called hybrid seed, labeled with "F1 hybrid", where it really means "true bred phenotypical F1 hybrid"

PC

This post was edited by PupillaCharites on Sun, Jan 18, 15 at 5:36

I think Sungold has more than two parents which is why it so hard to grow out and stabilize

@Richard Allan, if that was the case then the plants grown from seeds wouldn't be uniform. If they were all clones, then I'd agree it's possible. However, the fact i can buy seeds and have all the plants be the same tells me that both the parents are True Breeding heirlooms/OpenPollinated