Frost and Cold Tolerant Tomato Breeding including epigenetic and regular genetic

[Steph S]

If I'm not mistaken, this fruit is starting to blush after heavy rain was followed by a cold night.  Pic taken yesterday.  Noticed that it hasn't caught up any fruit in that cluster as the plants in the greenhouse have done, although it does have some new sets in other clusters.  Putting it all into getting that first one ripe, this is less than 30 days from setting and ahead of anything in the greenhouse.
Today was 47 F and rained all day, the exposed plants looked so miserable I managed to get a tarp over their shelter to keep them from being soaked all night as well.  Highs forecast around 50 F for the next two days, lows in the 40's.
Tempted to pick that fruit and let it ripen indoors. 

[Joseph Lofthouse]

I have de-hybridized SunGold two times. I didn't recover the taste in either attempt.

The first time, the ecosystem did selection. I ended up with yellow fruited tomatoes with sizes between 0.3 ounce and 4 ounces.

The second time, I intentionally selected only for flowers with exerted stigmas. I abandoned that project after I discovered the truly promiscuous flowers of Solanum habrochaites and pennellii.

[Roland]

A lot of people try to de-hybridized SunGold F1, but it seems all fail to get the perfect taste from SunGold.
Also a lot of F3, F4 plants show no Orange color and I assume this is because of a cross made by the external stigma.

So probably many genes make the special SunGold taste. And to get a de-hybridized plant with selection for many genes we need 1.000 to 10.000 plants in the F2 and F3`s to compare and select the best.
So im always wondering how many Fx plants where used to de-hybridize SunGold?

What do u guys think, is the orange color in SunGold because of the recessive gene Tangerine?

[Joseph Lofthouse]

The second time I grew F2 seeds from SunGold, I grew around 72 plants. I didn't know at the time about the exserted stigmas of SunSugar F1, or I would have grown that instead.  I wasn't chasing flavor with either dehybridization episode. I was interested in local adaptation with the first, and in exserted stigmas with the second. SunGold is super early in my ecosystem. With my short season, that is a trait worth exploring.

Due to the odor of the plants, I speculate that they are recently descended from Solanum habrochaites.

I can't speculate at all regarding what genetics might be involved with the orange coloration. None of the ancestors of the Beautifully Promiscuous and Tasty Tomatoes project were known to be orange fruited, but the trait is common in the descendants.

[William Schlegel]

https://wildboarfarms.com/product/big-sungold-select/

https://www.adaptiveseeds.com/product/vegetables/tomatoes/tomato-sungella-organic/

https://osseeds.org/ossi-varieties/santiam-sunrise/

https://www.adaptiveseeds.com/product/vegetables/tomatoes/cherry-grape/tomato-santiam-sunrise-organic/

It looks like OSSI's Andrew Still has a OSSI pledged version.

I doubt growouts by most amateurs are very large. In the range of 100 plants or less. My own have been very small, I think this year for instance I decided to grow a pinch of seed as a clump. If I really went after it I would grow maybe five F1 plants of Sungold F1 or Sunsugar F1 and then save a couple ounces of F2 seed that I would direct seed.

http://jandlgardens.com/xencart/index.php?main_page=product_info&products_id=182

http://jandlgardens.com/xencart/index.php?main_page=product_info&cPath=1_76&products_id=341

The tomato I found in my 2017 garden with the best exsertion about 4 out of 5 plants was Blue Ambrosia bred by Lee Goodwin from his own Ambrosia Gold and Bosque Blue. I suspect from his description that Ambrosia Gold might be a Sungold dehybridization that had higher brix. If so Sungold is something akin to a initial cross grandparent of my exserted tiger. I got exserted Tiger by growing out two generations of Blue Ambrosia descendents till I got an F2 with stripes from Amurski Tigr.

I saved all the Blue Ambrosia seed then planted it all to find F1s. Then planted all of that to find F2's. I mixed in a few other F2s as well for a massive F2 grow out in 2019.

This process was a lot more fun than dehybridizing Sungold F1 would be for me. If I were going to grow Sungold out for dehybridization I wouldn't start with straight Sungold F1. I would cross it with something else. Maybe Exserted Tiger to try for an orange with blue and stripes and exsertion. Though in truth I would use exserted orange or another orange from the promiscuous project for that goal.

That said from my 2017 investigation of germplasm for my direct seeding project Sungold segregants are probably a top ten for earliness and maybe a top three or so if you factor in color and flavor. Given its ready availability I would encourage anyone to buy a little basket of Sungold F1 tomatoes from their local farmers market and eat them but save a few seeds and grow them. Or a single Sungold F1 plant. Cheap and easy to obtain germplasm for tomato breeding. Also you could chase earliness with Sungold F1 dehybridization.

Where the orange comes from?!

There is a line of thought that Sungold F1 gets part of its signature flavor and spicy foliage smell from recent habrochaites ancestry. Some of our promiscuous project plants seem to be orange. Exserted orange was supposed to be a habrochaites F1 with Big Hill instead it came out as a domestic orange. We thought pollen contamination from something like Sungold F1 but are still uncertain on that. In fact some are coming out as cherries and others as bicolors. Though could just be this tangerine gene. Also what Joseph said while I was typing.

[Garrett Schantz]

The F1 between my s. pimpinellifolium and s. habrochaites were orange.

The habrochaites ripened to a off-white color, the pimpinellifolium ripened to red.

I will be trying to pollinate some probable exserted Alberto Shatters with some "wild tomato species" to try and figure out how certain colors appear and segregate.

I am assuming that SunGold has some habrochaites like you guys are thinking.

I bought a single SunSugar plant from Walmart, I haven't really checked the flowers out yet. Should have fun genetics.

[Garrett Schantz]

SunSugar F1 is definitely exserted!

I have heard that it doesn't taste quite as good as SunGold - I wouldn't know as I haven't grown SunGold before.


I will try some crosses with this, maybe some desegregation projects.

I will be trialing out the offspring for cold tolerances, I suppose.

Alberto shatters and a bunch of other plants already seem exserted, wouldn't hurt to use their pollen on some SunSugar plants.

[William Schlegel]

Yeah I found a Sungold or Sunsugar at the local Ace hardware with exsertion and I carried it around awhile but I told myself that 500 or so tomato plants is enough and put it back.

[Steph S]

LOL William.  Such self discipline. 

[Roland]

In 2021 i grow my first Sungold F1 and did do some crossbreeding with Sungreen F1 and Sungreen 4029. Think i can tasted it in a week.
For self-pollination I removed the petals and left the pollen. hopefully this will stop the bees from visiting the flowers.

Why would u guys prefer to use SunSugar instead of Sungold for Cross breeding?

@ Joseph, 72 F2 plants is still a lot. Can u tell something about the segregation? Like color, size earliness ore other interesting traits?

[Joseph Lofthouse]

The Sun_____ family has three traits that are of interest to me. 1) They are very early. 2) They carry genetics for exserted stigmas. 3) They are orange-fruited. In SunGold, the exserted stigma trait only shows up in the F2. In SunSugar, it shows up in the F1. That is why I would use SunSugar if I were doing breeding work with the Sun family. I am all about getting rid of the inbreeding meme regarding tomatoes.

I think that SunGold had about 5 plants of the 72 F2 with exserted stigmas. That was the only trait I was interested in. There were a few red-fruited tomatoes in the F2. Consistent with a cross pollination rate of 3% to 5% in domestic-type tomatoes. There was variation in size and earliness in the F2. They were all cherry tomatoes. Some smaller than the F1. Some larger. They were all early, some more than others.

The first 4 photos are about F4 of my first dehybridization of SunGold. The flower is an F3 from the second dehybridization.

[Roland]

My Sungold F1 has exserted stigmas.

[Steph S]

Flower color in Joseph's picture is consistent with  Beta orange genetics, that is also found in wild relatives.
tangerine t is the other common orange gene, found in domestic tomatoes.

There is an explanation for why the orange would appear from plant parents that weren't orange.  Beta is only expressed in a red background.  So if one of the parents was yellow or bicolor afaik, Beta could be present but would not be expressed.  In an F1 cross with a r/r red the F1 will ripen orange-red.  So you can see Beta is present even in B/- but only if the base color  is red.    Some recent work suggested Beta is an allele of the same locus as oldgold and ogc oldgoldcrimson.  The Beta allele results in a high content of Beta carotene instead of lycopene.

Tangerine orange is a different locus and works very differently.  It is recessive, so t/- F1 will not show any orange.  However it can be expressed in any background, red, or yellow or bicolor afaik.  The flowers of a t/t tangerine plant will have an orange anther cone and the petals as they dry turn peach orange instead of straw yellow.  The intensity of color does vary depending on the background and possibly some modifiers, but it is recognizable if you're looking for it.  Tangerine orange fruit is rich in prolycopene, and low in beta carotene.  So they are nutritionally different as well.

There are other orange genetics (Delta, apricot) but they are rare by comparison.  Apricot has almost white flowers.  Delta fruit is more like a shade of red than orange.  I haven't encountered either of these in orange fruit I've grown.

[William Schlegel]

"There is an explanation for why the orange would appear from plant parents that weren't orange.  Beta is only expressed in a red background.  So if one of the parents was yellow or bicolor afaik, Beta could be present but would not be expressed."

Not sure if I completely follow but exserted orange segregated last year to orange and bicolor and the mother of the original cross was Joseph's bicolor big hill.

I liked those extra orange anthers you shared awhile back. Wonder how flower color affects pollinator visitation.

Joseph noticed awhile back that Jagodka had higher flower visitation by pollinators. Which is part of why he included it in so much ancestry of his current varieties. Thought it seems like wild species like S. Habrochaites do things like produce abundant pollen which might mean bees get more. Maybe Jagodka produced more pollen?

[Joseph Lofthouse]

The flower in this photo is from LA1777. The very plant that was the first wild ancestor of the Beautifully Promiscuous and Tasty Tomato project. I love the orange anthers, though I haven't really noticed that trait since.

Jagodka was the variety that triggered the project, because the Bumblebees were always fussing with it. That got me to thinking about how to increase biodiversity and out-crossing in tomatoes.

Jagodka was used as a parent to Big Hill, because Jagodka is cold tolerant, super early, and highly productive. It was my main market tomato for some years.

Big Hill was used in the project, because the fruits are tasty (not red), and because it was an early beefsteak with open flowers.