Sungold F1 and Sunsugar F1 breeding with and dehybridization

[William S.]

Sungold F1 and the perhaps closely related Sunsugar F1 are interesting tomatoes to me.

I am also growing some Sungold F1 for the first time in a couple years because I think it is an important flavor standard. Though I almost always at least grow some segregating Sungold descendants.

Last year I noticed a red one in a clump of dehybridizing Sungold and saved some seed.

However, I noticed a post today on Facebook by Frogsleap farm about the Beta allele and it stated that the Beta allele is dominant over red. In the comments below the post someone asked about common ones and the reply was Sungold. So Sungold has a dominant gene for orange. So we should be able to cross Sungold with any other tomato and it should show up as a dominant this Beta allele. So my red F5 Sungold descendant could be a recessive coming out. Now I do not know if there is a red recessive in Sungold F1. A isolated grow out of Sungold followed by a very large F2 growout would show us if that is indeed the case.

You see Sungold is also a fairly common source of an exserted style / stigma. I have found Sungold and Sunsugar plants on more than one occasion at a local hardware store or nursery with really pronounced exsertion.  So I assumed my red one was a new cross and that red was dominant. Not a safe assumption apparently. Oh well I already mixed it into a direct seeding mix- probably would not have knowing this. That said I am still sort of happy to have Sungold and its desegregated or desegregating descendants in my garden. The descendants seem to taste good and I think they are a good addition.

I do think that Sungold F1 and Sunsugar F1 are really pretty decent breeding material. They have good flavor, are early, and because they are so popular it is hard to not find a seed packet or a started plant from a nearby source.

[Joseph Lofthouse]

I grew out 72 SunGold F2 plants one summer. A few of them produced red fruits. But not anywhere near 1/4.

If anything, the ratio of red to orange was more like 1/16th, perhaps indicating that two recessives are involved.

This summer, I'm growing out the (purported) F1 hybrid of a manual cross between exerted SunSugar and yellow fruited self-incompatible tomatoes from the Beautifully Promiscuous and Tasty Tomato project. It would be really clever if orange fruits are dominant.

[Steph S]

One year we had a couple of red cherries turn up in a commercial packet of Sungold grown at the farm.  The red ones were not tasty.  I guess the best explanation would be an unintended cross, since both of Sungold's parents must be stable for two Beta alleles.   Just on the reasoning that it would be impossible to maintain unstable parents for an F1 cross.
The Beta orange is an interesting trait.  It isn't fully dominant, but is semi-dominant and produces orange-red fruit when B/- heterozygous.  The locus for Beta iirc has been identified as the same locus as OG 'old gold', a pigment intensifier.   So there are combinations of alleles possible in unstable generations which might explain some unique flavors that are difficult to stabilize.   
Beta orange only occurs in a red background, so there are no Beta orange with underlying yellow genetics as is found with tangerine.
In addition, there are a number of known genes which act as intensifiers of the beta-carotene production under Beta. 
So it is not inconceivable that suppressor alleles also exist, and these mutants might account for the 'double recessive' number of reds in that F2.

[Andrew Barney]

Interesting topic.

I am not all up on tomato genetics, but could sungold be a cross of a Beta x tangerine?

Has anyone taken the best tasting F2 and back crossed it to sungold? Might help stabilize some of the rare segregating recessive genetics.

While I haven't had sungold in a few years my memory serves that while sungold is good, that some of it is hype. The new orange dwarf cherry I snagged from Rocket Farms seems like it might taste better to me, and has a dark orange color, which I like. I am contemplating crossing it with exerted Big Hill.

[William S.]

I think that crossing Sungold F1 with other fruity and orange tomatoes might have some interesting and potentially very fun results. I think that crossing an orange tomato either Sungold F1 or your orange dwarf with Big Hill would have the potential to create something a lot like Exserted Orange or its sister variety Orange Hill. If you don't have seed for Exserted Orange or Orange Hill I have plenty of seed for both, I think. In the last generation I grew last year I thought Exserted Orange seemed pretty stable for orange color and exserted stigmas but it might be worth growing a larger growout of the latest seed from that- F4 I think just to find out. Some of the plants are more of an orange bicolor than a straight orange. I think though that it is possible that Exserted Orange x an Orange Dwarf would make for a easier project if your goal is an orange dwarf with exserted stigmas.

I think any of the tomatoes known for tropical fruit tastes or just fruity tastes might be good candidates for intercrossing with other fruity flavored tomatoes as they could end up making for good flavor combinations or even discovering new flavors.

Also, it might be interesting in terms of creating open source hybrids to try crossing some of the various dehybridizations of Sungold and SunSugar with each other to see if any of the hybrid offspring are markedly more like Sungold F1. It might also be worth it to take those dehybridizations and cross them with other fruity tomatoes to see if any of the resulting hybrids might make a good open source F1.

Honeydrop is an OSSI registered Sunsugar dehybridization and Sunviva which I don't think is a dehybridization is a European open source tomato with fruity tastes. Brad Gates has Sungold Select. Santium Sunrise from Adaptive Seeds sounds like it is not just a dehybridization as they talk in the description about crossing with Russian cherry tomatoes. Sungella is also available from Adaptive Seeds and is a dehybridization. Ambrosia Gold is a Lee Goodwin introduction which he compares to Sungold on his website and also a parent of Blue Ambrosia. Then Craig LeHoullier made a recent comparison of Dwarf Eagle Smiley with Sungold which doesn't have shared ancestry. There is also the fruity flavors coming out of Joseph Lofthouse's promiscuous project and other varieties known for their fruity tastes like Persimmon and Uluru Ochre. Often orange tomatoes and orange bicolor tomatoes have these fruity tastes.

I am growing a new to me Brad Gates introduction called Atomic Sunset this year it is also an orange bicolor but with stripes and anthocyanin.

[Andrew Barney]

I think that crossing Sungold F1 with other fruity and orange tomatoes might have some interesting and potentially very fun results. I think that crossing an orange tomato either Sungold F1 or your orange dwarf with Big Hill would have the potential to create something a lot like Exserted Orange or its sister variety Orange Hill. If you don't have seed for Exserted Orange or Orange Hill I have plenty of seed for both, I think. In the last generation I grew last year I thought Exserted Orange seemed pretty stable for orange color and exserted stigmas but it might be worth growing a larger growout of the latest seed from that- F4 I think just to find out. Some of the plants are more of an orange bicolor than a straight orange. I think though that it is possible that Exserted Orange x an Orange Dwarf would make for a easier project if your goal is an orange dwarf with exserted stigmas.

I think any of the tomatoes known for tropical fruit tastes or just fruity tastes might be good candidates for intercrossing with other fruity flavored tomatoes as they could end up making for good flavor combinations or even discovering new flavors.

I think i have seed for Exerted Orange, but probably not Orange Hill. I didn't plant it this year as I needed to prioritize for some of the more wild ones this year. But would be good to add to the planned dwarf trialing for next year.

[Steph S]

Interesting topic.

I am not all up on tomato genetics, but could sungold be a cross of a Beta x tangerine?

Beta and tangerine are not the same locus, so you can't cross them and expect them to combine as an orange fruit involving both.
IDK if a tomato exists with both Beta and tangerine, but they are different biochemical pathways which result in orange color.  Beta interrupts the lycopene pathway to produce fruit rich in beta carotene instead, while tt tangerine interrupts the same pathway very early on, so that the dominant chemistry is prolycopene in that orange color. Since tangerine blocks lycopene synthetic pathway earliest in the game, I would expect a Beta BB and tt tangerine plant to be just like any tangerine tomato, biochemically.

Both have unique health benefits as a source of carotenoids - prolycopene in particular is said to be easily assimilated in fresh fruit vs lycopene which is more bioavailable after cooking.  We all know about beta carotene thanks to carrots (well speaking as a northerner, anyway! and chanterelles too!)

It's all good for you, but from a breeder perspective you'd best know whether an orange fruit is Beta or tangerine before you set to cross it with another orange fruit.

I also believe that some unusual tastes 'tropical' and so on associated with Beta tomatoes are a legacy of the wild relatives that donated the Beta genes and other traits. They don't actually depend on the Beta genetics, but are baggage brought over in the package that turns out to be a nice plus.   
Tangerine is something I am a bit mystified taste wise, perhaps insufficient experience, but I believe that prolycopene itself is very mild tasting.  I associate mild and melony flavors with the majority of tt tangerine plants I've grown.   So if there are great tasting tangerine tomatoes, they probably get their dominant taste biochemistry from something other than prolycopene.  (Not to diss the melony taste either - some of these fruits are very 'morish' in spite of the subtle taste.)

[Vesa Tee]

… could sungold be a cross of a Beta x tangerine?

I have made a cross between a tangerine and a dominant orange, most likely Beta. The F1 was a very clear orangish-red. Not sure if it was orange enough to compare with sungold but it was still a strange orangish colour. Difficult to compare too as my F1 was much larger than a cherry. I have been thinking myself too if sungold might have one Beta parent and another yellow or tangerine, like the F1 being BbRr or BbTtRR. Since tangerine and yellow are recessive, they would not block the lycopene pathway when at least one parent has functional R.

Gobstopper is supposed to be dehybridization of sungold, and it is a yellow with very green gel or a simple GWR. Haven’t seen people reporting yellows from sungold volunteers though, usually people reports oranges and reds.

[Steph S]

That's an interesting point about the Rr possibility.
In fact there's no reason a tomato couldn't have BB tt at the same time, nor that a yellow tomato might have BB present but suppressed.  There are a lot of variations in yellow color of fruit which I haven't seen explained entirely.   rrtt is common enough but there are more shades of yellow than just that one.

So many people have posted here and there in the forums about planned or active dehybridizations of Sungold, but I have never done anything with it myself, so all my comments about it are theoretical and not based on observations.   I did start a load of them this year for my friend's farm though, so I'm expecting to get a close look at those flowers at least. 

[Greenie DeS]

I think the sungold sweet with the black smoke flavours would be one of many perfect possible tomato flavours. I've never tasted a dehybridization of it that really captured that flavour, though (which is a little too sweet for me normally).

[Andrew Barney]

I've never tried breeding it, but considering there are few to none of the dehybrid projects with anything close from what I've read, it makes sense that there might be some complex interactions of multiple genes. Which is why I think someone should take their best tasting dehybrid and do a backcross and see if round 2 at dehybridization can stabilize those taste genes.

[Vesa Tee]

I haven’t played with Sungold much, in fact just tested it first time last season to see what is the big fuzz about it. Needed to sniff that funny smell of the leaves and try the taste of course. I got almost like a small allergic reaction from the smell, the staste was good and I can see why people generally like it. But will not likely grow it again.

If the heterozygote tomato colour genes, like BbTtRr, contribute to the flavor, by definition, there is no homozygote version of that. It would be the perfect IPR protection plan after the invention of the F1, a flavor that cannot be recreated by any other way than crossing the original parents. People do report challenges of getting the Sungold stabilized which might point to this direction. But sure, there must be more to the unique flavor than these genes, the funny smell likely demonstrates that.

BTW, Gobstopper makes an excellent parent for a F1. I find Gobstopper little short in flavor and sweetness, however, a F1 from a cross with it was super sweet. I don’t typically grow F1 generation again from my own crosses but would consider growing this one.

[Nicollas]

Maybe at this point it is worth the try to make another sungold-ish hybrid by crossing a SC hirsutum with a B tomato

[William S.]

Maybe at this point it is worth the try to make another sungold-ish hybrid by crossing a SC hirsutum with a B tomato

I am not sure what you mean by B but this website suggests Brandywine may be a parent:  http://www.tomatodirt.com/sungold-cherry-tomatoes.html

I think based on the Solanum hirsutum = Solanum habrochaites hybrids I've grown that if the theory that some recent habrochaites is true in Sungold it would have to be a large introgression rather than full habrochaites. Because F1's seem to be pretty much wild type.

So I think the hybrid would be more like something like a stabilized version of the fruity promiscuous project tomato I selected last year crossed with a Brandywine. Though I do not think I agree with Brandywine at least not as a F1 parent. Because when we cross beefsteaks with cherries we often get some mini beefsteak types like what I had last year with my "little pumpkins" promiscuous project selection from last year. Nothing like that has segregated out of Sungold for me. So while Brandywine could be a grandparent I don't think it was a parent. My educated guess is that both inbred line parents are cherry tomatoes and that at least one of them has a big habrochaites or pennellii introgression but that both are probably decent tasting cherry tomatoes. That does not mean that a Brandywine x Fruity Stable SC Promiscuous project wouldn't be interesting and if there is both Brandywine and Habrochaites ancestry in Sungold it would be possible that the flavor resulting could be comparable.

I couldn't remember and Googled the Sungold creator just now it is Tokita Seed. http://tokitaseed.co.jp/eng/ucatalogue_e.php

Looking through their catalogue Sunpeach, Sungold, Sunorange, Sunchcola, Sungarnet, Sungreen, Sungreen 3014, Sungreen 4029, Sungreen 8837, Suncitron, Suncitron 8805, and five varieties of Suncherry (red) are their current cherry tomato lineup. From reading the descriptions some of them include other flavors such as citrus. It would be interesting to try more of them- Johnny's Selected Seeds has Sungreen 4029 and Sunpeach. It also occurs to me that just possibly some of the others likely contain one of the same parents/genetics as Sungold F1. I've never seen a green when ripe from segregation so that must come from a different parent.

Though I still maintain that crossing different desegregated lines could result in comparable flavors in the resulting hybrid.

Just thinking about similar things to Sungold: here is a new hybrid F1 orange cherry tomato called Citrine that Johnny's says "thanks to NCSU for working with us to develop this variety"

https://www.johnnyseeds.com/vegetables/tomatoes/cherry-tomatoes/citrine-organic-f1-tomato-seed-4025G.html

[Nicollas]

I was thinking of doing an F1 hybrid between an habrochaites and an OP tomato with BB, hoping to reproduce some sungold vibe (or better).

Maybe Del could be used too