Open Source Plant Breeding Forum

Darrel Jones and Joseph Lofthouse have spent some time and energy on frost and cold tolerant breeding of tomatoes. We just did some discussion of this in the climate change breeding thread but I thought a dedicated thread might be useful here.

There is a history of some strains of domestic tomato having more cold or frost tolerance. There are also wild tomato species with more cold and frost tolerance. So through both epigenetic and genetic means we may be able to produce more cold/frost tolerant tomatoes to extend the growing season.

Quote from: William S. on 2018-12-02, 09:19:28 AM
There has been a lot of discussion about epigenetic change in Tomatoes over on the homegrown goodness forum and possibly another forum like tomatoville especially in regards to Darrel Jones initiated cold/frost tolerant tomato breeding project, Josephs trays full of frosted seedlings, some Russian tomatoes, and the wild tomato species with better cold and frost tolerance.

In 2018 I got no spring frosts after planting tomatoes. However in 2017 I got two frosts after transplanting at least the latter of which impacted much of my direct seeding experiment as well. Most plants that were frosted twice died. Most plants frosted once survived by resprouting from the base. One Peruvianum complex plant survived both frosts with top growth intact. Habrochaites survived by resprouting.

I included some of the Russian genetic strains in this. They did not impress particularly if they had resistance I think it must have been epigenetic and inactive in 2017. It's possible that the shock of being frozen once or twice may have activated some epigenetics.

A few rare plants planted between the two frosts survived with top growth intact despite every plant surrounding them succombing. These results were pretty nonsensical. For instance one Blue Gold plant a Brad Gates variety not chosen for frost tolerance survived with top growth intact while many many frost or cold hardy strains succombed and every other Blue Gold individual. However the frozen to the ground plants resprouted and did set fruit as well.

I also learned that most inch high tomatoes direct seeded survived.

I also direct seeded more tomatoes the next day. Ultimately I had too many tomatoes in 2017.

I am pretty willing to flirt with that last spring frost or two because I now know I can reseed immediately, that most tomatoes will survive being top killed once, and if there are epigenetics at play they may be being activated, and soil moisture is great I can transplant without watering anything but the flats or direct seed without watering, which means I may not need to water until July.

In 2017 my fall killing frosts weren't very telling. A single big very hard fall frost killed everything. 2018 I had weaker fall frosts and they took out domestic tomatoes first then wild tomatoes like Peruvianum complex and habrochaites lived longer both from top growth and resprouting. Though even domestics were sometimes killed in layers.

It would be interesting to have a bit of an experimental facility to test and play with both epigenetic and genetic cold and frost tolerance in tomatoes. A dedicated refrigerator would work for cold tolerance- Darrel Jones suggested that a refrigerator test would quickly separate strains there by turning non-cold tolerant strains to mush. However freezing is trickier. It would be nice to be able to freeze tomato plants under controlled conditions. Darrel also explained go us that the moisture with the frosts is important- leaf dry vs. Leaf Wet frosts.

Quote from: Carol Deppe on 2018-12-01, 11:22:20 PM
Joseph, when you are growing stuff you know is outside it's comfort zone, do you direct seed, or start it in a greenhouse?

I'm suspicious that some, maybe most of what we experience when we adapt varieties to our region is epigenetic rather than genetic change. I speculate that most plants have a basic adaptation that is fairly wide, but this adaption is narrowed and optimized for any specific environment by heritable epigenetic modifications. Essentially a program on top of a program. I speculate that what gets you from one epigenetic subprogram to another is a serious shock of some sort. Heat shock, cold shock, etc. Something extreme enough to make the plant stop growing for a while but not so extreme it kills the plant. Maybe the nature of the shock induces a specific change to the correct alternate epigenetic program. Or maybe it just causes the plant to try a different one of it's epigenetic programs at random, with some plants hitting the right one.

If something like this is going on, Joseph's transition year might be the year that causes enough of a shock to trigger change in epigenetic program but not so much it kills unaltered plant first.

So if all this speculation was actually truth, we might be able, for example to get a tomato variety to become more freeze-hardy by subjecting seedlings to cold shocks and then saving seeds. Shades of Lysenko. However not for the reasons he supposed. No inheritance of acquired characters. Just an environment induced epigenetuc program change.

This is all speculation. I set it out because it we can test these ideas. And they have a whole lot of plant breeding implications.

A little later after a couple hrs reading about plant epigenetics on internet. Lots of people have approximately same ideas as outlined above, with much work on biochem of epigenetic changes on DNA. And there is much enthusiasm for potential in plant breeding. And much work happening attempting to get plants to produce "epilleles".. However there seems to not be a single variety developed based upon an epigenetic change yet.

I really appreciate seeing epigenetics being discussed alongside breeding efforts!

I recently came across some research on Goji berry breeding, which indicated that there is the potential to cross tomatoes and other Solanaceae with Lycium sp. It's mentioned under Hybridization here:  https://www.researchgate.net/publication/325759407_Gojiberry_Breeding_Current_Status_and_Future_Prospects

The study states that out of seven lines from 21 cross combinations they were able to obtain two flowering and fruiting plants.

This may not necessarily count as a true tomato breeding project but given the cold hardiness of many Lycium sp. it may be worth looking into. There are certainly many more factors to consider but it seems like a potential path toward a perennial zone 4 tomato-like plant. Perhaps a tomoji?

I hope this doesn't diverge too drastically from your original subject but I thought it should be mentioned.

I wonder what conditions are best for cold tolerant tomatoes.

I live on the Pacific coast of Canada.  Our summers are what most everyone else in North America would call 'cool'. Both days and nights too. We don't have air conditioning, and I don't sit around outside in the evening.

However, we don't have late frosts.  Our usual time to plant tomatoes is late in May, but that is not to avoid frost, but to hope for some warmth.   I have planted out tomatoes in April in years that I have been travelling in May, and they've grown as usual. 

Are Russian tomatoes like the Saraev ones bred to do well in these conditions?

Or do they withstand the occasional night frost but then revel in hot days to compensate?

I wasn't impressed by any of the Saraev tomatoes I tracked down. I suspect it was epigenetic. Darrel Jones seems to be the Guru on this. He has a bit of something in the works. I was recently visiting relatives in Vashon WA and they had a live but unproductive tomato plant in november. A cold tolerant tomato could be huge there.

Have you seen that new cloudy day hybrid? That could be a good dehybridization project.

Well, I will have to try that one.  Has everything I need:  Variety thrives in cooler temperatures; plants laugh off early and late blight. 

Well, almost everything - comments on its looks, but there is no mention of it being delicious.

Yeah it could be perfect for one of our colder cloudier summers here. Some years it's hot and the skies fill with smoke, some years it rains alot... Never know what your going to get.

A summary of what I think I have learned about cold/frost tolerance in tomatoes....

There seems to be two different traits that may be useful, and don't seem to be closely related to each other: 1- frost tolerance. 2- ability to grow in cool temperatures. The winner of my frost tolerance trials was Jagodka (Ягодка) a variety from the Vavilov Institute of plant science in Russia. It has low tolerance to frost, but a high ability to grow well during cold weather, and in my garden with intense radiant cooling at night. Most of the Russian varieties that I trialed were a bust -- My continental desert climate is radically different than the maritime climate of Saint Petersburg. The runner up in my cold/frost trials was a variety named Matina.

Some years, my domestic tomatoes have been frozen for two months before the Solanum habrochaites plants finally get frozen.

There seem to be large differences in early spring frost tolerance between varieties.

Tomatoes in my garden would benefit from developing resistance to flea beetles, because plants are severely damaged by them first thing in the spring. The earlier I plant them, the more predation there is, so increased frost tolerance would ideally be paired with increased resistance to flea beetles. 

Tomatillos are more frost tolerant than tomatoes. I often use tomatillos as a control in my seedling frost tolerance trials, because if the tomatillos also get killed, then I know it was a really hard frost.

I think that frost tolerance of seedlings may not be closely related to cold tolerance of end-of-season plants.

Some of the wild species, and some of the interspecies hybrids can have their tops killed by frost or winter weather, but they have the ability to survive and re-sprout from the basal stem.

My frost/cold tolerance project is currently on hold. I am focusing my tomato breeding efforts on creating a genetically diverse, self-incompatible tomato population. Once that is in place, I expect to restart other projects like cold/frost tolerance. The varieties that were previously winners of my cold/frost tolerance trials are being merged into the beautifully promiscuous tomato project.

I'm wondering if something as simple as refrigerating a ripe tomato fruit for a month prior to harvesting the seeds could trigger an epigenetic change towards more cold tolerance. Or how about freezing the fruits before extracting seeds?

I want to focus more effort towards selecting for tomatoes with the ability to volunteer. I think that in my garden, that may also inadvertently be selecting for some measure of frost tolerance, and ability to grow in cool temperatures. 

And finally, just about all of my selection work is done on segregating hybrid swarms. I don't have any good way of differentiating allele-genetic differences from epi-genetic differences. Mendelian genetics doesn't seem to be very applicable to my methods.

Quote from: Joseph Lofthouse on 2019-01-12, 11:41:33 PM
I want to focus more effort towards selecting for tomatoes with the ability to volunteer. I think that in my garden, that may also inadvertently be selecting for some measure of frost tolerance, and ability to grow in cool temperatures. 

I have lots of tomato volunteers both in spring and in late summer/fall. There is definite variation in how much frost they take. I'v seen spring volunteers survive when most didn't as well as some late ones croaking in the first fall frost and some holding on till a harder freeze. I don't have a real need for frost tolerant tomatoes so never gave them much attention. I suspect once you achieve the goal of volunteers the rest will be easier. I have to wonder though, are cold weather tomatoes gonna taste like tomatoes?

I think in my garden our thoughts on domestication of Peruvianum complex lend themselves best towards this. It's a champion volunteer in my, Andrews, and Joseph's gardens. In my garden it's shown interesting frost and cold tolerance. Joseph has started selecting it for flavor. I've decided to focus some on both potential bridge lines and possibly some embryo rescue as it would be neat to A. Cross it into domestics, and B. Cross domestics into it. 

Quote from: Joseph Lofthouse on 2019-01-12, 11:41:33 PM

I'm wondering if something as simple as refrigerating a ripe tomato fruit for a month prior to harvesting the seeds could trigger an epigenetic change towards more cold tolerance. Or how about freezing the fruits before extracting seeds?

I think it could be a very good technique. I've thought about it myself. In fact,  it would be nice if we could artificially have a chilled room that was cold but not freezing at the times of growing we wanted to induce an epigenetic change (which I suspect over time epigenetic change can induce more permanent genetic changes), but over several generations.  This I suspect that line would grow better in such conditions.

Simply planting seeds early direct seeded might select naturally for early frost/cold tolerance,  but late cold/ frost tolerance might be a whole separate set of genes or epigenes.

Quote from: reed on 2019-01-13, 03:55:02 AMI have to wonder though, are cold weather tomatoes gonna taste like tomatoes?

Not in my garden. Any cold tolerant tomatoes that I develop are likely to taste like an exotic tropical fruits, guavas, plums, mangos, etc. I'm pretty much done with lycopene bitterness. One of the great joys of working with the interspecies tomatoes, is that it has taught me that tomatoes don't have to taste like the highly inbred, genetically fragile plants that we inherited from the corporation.

Quote from: William S. on 2019-01-13, 06:09:01 AM
I think in my garden our thoughts on domestication of Peruvianum complex lend themselves best towards this. It's a champion volunteer in my, Andrews, and Joseph's gardens. In my garden it's shown interesting frost and cold tolerance. Joseph has started selecting it for flavor.

I am also selecting the peruvianum complex for fruit size. And I'm growing it next to other wild species, and to the interspecies hybrids, hoping that some natural crossing will occur. Peruvianum doesn't seem to be a good pollen donor to habrochaites, because when I grew a single habrochaites plant in the peruvianum patch, it didn't set seed. 

After I took this photo, comparing the typical small peruvianum fruits to a larger peruvianum fruit, I found a plant that had even larger fruits.... When I grow tomatoes 9 inches apart, it's hard to pay attention to individual plants, until something grabs my attention. Larger fruits certainly did. I saved seeds separately from larger fruited plants, and am intending to do early selection next year by culling plants with small fruits early in the season so that they don't shed pollen for small fruits into the patch.

Quote from: Joseph Lofthouse on 2019-01-13, 08:34:33 AM

After I took this photo, comparing the typical small peruvianum fruits to a larger peruvianum fruit, I found a plant that had even larger fruits.... When I grow tomatoes 9 inches apart, it's hard to pay attention to individual plants, until something grabs my attention. Larger fruits certainly did. I saved seeds separately from larger fruited plants, and am intending to do early selection next year by culling plants with small fruits early in the season so that they don't shed pollen for small fruits into the patch.

That's way cool!

That reminds me of another idea I had once. I suspect just growing plants next to each other that epigenetic influence can occur from chemicals leached into the soil.

One year I grew a whole patch of my purple stalked corn. That year and the following year after (maybe two) the grass weeds turned a heavy red shade. It did not seem like a coincidence. Obviously they couldn't have been influenced by pollen. It made me wonder if grinding up dessert adapted plants like yucca and spraying it on as fertilizer could help produce a more desert tolerant domestic crop like corn.

Quote from: Andrew Barney on 2019-01-13, 09:01:24 AM
That's way cool!

That reminds me of another idea I had once. I suspect just growing plants next to each other that epigenetic influence can occur from chemicals leached into the soil.

One year I grew a whole patch of my purple stalked corn. That year and the following year after (maybe two) the grass weeds turned a heavy red shade. It did not seem like a coincidence. Obviously they couldn't have been influenced by pollen. It made me wonder if grinding up dessert adapted plants like yucca and spraying it on as fertilizer could help produce a more desert tolerant domestic crop like corn.

Course it could just be that corn being a heavy feeder temporarily depleted phosphorous from the area. Google tells me that nutrient deficiency causes red foliage.

Plants use red like sunscreen.

Quote from: Joseph Lofthouse on 2019-01-13, 08:34:33 AM
Not in my garden. Any cold tolerant tomatoes that I develop are likely to taste like an exotic tropical fruits, guavas, plums, mangos, etc.

Ah, you mean like the one pictured below, which came from your seeds. Looks like a tomato but tastes more like something that might be found under a tree in Hawaii. I called it Captain Crunch, cause it's crunchy when chomped on, very juicy and sweet. I think I sent some seeds back to you but don't remember for sure. Unfortunately it had little disease resistance as you can see by the foliage.  I like the flavor of my old red tomatoes but there is room for things like this in my garden too.

Quote from: reed on 2019-01-13, 03:11:09 PM
Ah, you mean like the one pictured below, which came from your seeds. Looks like a tomato but tastes more like something that might be found under a tree in Hawaii.

Yup. Like that!!! Tomatoes are a tropical species after all.

I was especially enthralled by the "high ummami" fruits and by the "fermenty" flavors.

I like red tomatoes fine, and yellow ones, and green ones, and bicolor ones, and orange ones, and fruity tomatillos, ground cherries, and tomatoes with new flavors like Brad Gate's Amethyst Cream. So I suspect I will like many of the new flavors Joseph finds for us but still eat some ordinary red ones too. I even like the ice cube flavored ones taco bell chops up and serves on their tacos.

As always, I started my tomatoes in regular garden soil, without bottom heat or supplemental lighting. As usual, some croaked. Every year I start them in a similar way and plant out under wall-o-water in March or April. Whether epigenetics or genetics, they seldom die in the spring any more. Those that do I simply replace.

I selected the first to come up, the subset that got secondary leaves while still in dim light (sunny windowsill, no supplemental lighting), and the best of those are now in my garden under milk jugs. Even with snow on the ground they're not complaining. One of the six is easily twice as tall as the rest and I'll be keeping an eye on it. Those six will be my seed tomatoes this year. Two of the other plants have been eliminated--one nearly died when it didn't get watered for a couple days, and the other was covered with aphids in the greenhouse.

Last year I was given a handful of plants. They had a very small survival rate under the same conditions. I think I ended up with fruit on two out of the ten. I was given two tomato plants this year. One croaked in the greenhouse, the other is out under a wall-o-water and getting frost damage even there.

Once I have the spring thing settled, I'll start working on autumn frost tolerance. I have noticed that the plants are much hardier than the fruit. The first frost of the season might not even touch the plants but the fruit bites the dust.

Currently watching seedlings germinate in cool soil. Solanum peruvianum, S. Pimpinillifolium, and S. Penelli  x domestic have won the germination race.

Joseph, do you like acidic flavors in your tomatoes also, or more just sweet and umami?

Quote from: Chance on 2019-04-19, 06:15:20 PM
Joseph, do you like acidic flavors in your tomatoes also, or more just sweet and umami?

I dislike bitter tomatoes. Anything raw, with nasty bitter red-lycopene flavor is close to unpalatable for me. In domestic tomatoes, I pretty much only tolerate yellow or orange tomatoes.

In the wild tomatoes, I am selecting for high ummami, fruitiness, lack of bitters, aromatic, and sweetness. (I'm selecting against red fruits.) People are describing them as guava, tropical, mango, grape, fruity, fermenty, etc... Flavors that might be more typical of physalis: ground cherry, cape gooseberry, etc...   

I've been trying to hand my toddler yellow tomatoes to see if I can get him to eat them. This morning he made a positive comment about how juicy the store bought cherry tomato I handed him was. Still didn't really eat it. Just bit it then rejected. Wanted it though.

Quote from: Andrew Barney on 2019-01-13, 09:01:24 AM

That reminds me of another idea I had once. I suspect just growing plants next to each other that epigenetic influence can occur from chemicals leached into the soil.

One year I grew a whole patch of my purple stalked corn. That year and the following year after (maybe two) the grass weeds turned a heavy red shade. It did not seem like a coincidence. Obviously they couldn't have been influenced by pollen. It made me wonder if grinding up dessert adapted plants like yucca and spraying it on as fertilizer could help produce a more desert tolerant domestic crop like corn.

Many years ago I was growing lemon thyme as a groundcover in with the raspberries (bad idea--it choked them out) and for the next couple years I noted that the raspberry leaves had a yellow edge just like the thyme. Again probably a nutrient issue, but interesting nonetheless. It was ONLY the plants closest to the thyme that were affected.

Starting my tomatoes in the normally unheated greenhouse this spring. Been unplugging the fan and plugging in a tiny Heater at night. Been interesting to see which species germinated first. A little worried about one night coming up in the forcast. Low of 29 F. Not sure if the heater can handle that. Might get nervous and bring them in.

Curious though if it affects their epigenetics to keep seedlings relatively cold.

I start mine in  an unheated cold frame. It's positioned against the south wall of the house, the back and floor are black, a few milk jugs of water take up the extra space.  Hasn't really been much of an issue this year but there have been many times tomatoes sprouted & survived in there when temps at night were intermittently below freezing. It isn't even all that well sealed, I throw a blanket over it on very cold nights but again that hasn't been an issue this year. Maybe I should have started them in February.  ;D

I find this epigenic thing a little hard to swallow but I'm intrigued. The premise being that environmental or other factors  can trigger the same genes to configure themselves in different ways?

Yep, basically as I understand it the epigenome is a system of regulatory switches that turn on and off genes and these changes can be heritable for a couple generations.

During some recent cold nights I took most of my tomato starts inside. Save two I left out just for curiosity. One survived a pimpinillifolium directly in line with my small heater. The other a potato leaf froze back badly. Perhaps it will resprout.

My garden is full of volunteer tomatoes right now, mostly the pimpinillifolium crosses I think.

I'v noticed in some years a dramatic difference in how the early volunteers respond to late frost but we haven't been below 50 F for quite awhile and don't really expect to be so guess there will be no volunteer frost tolerance trial this year.

Reading through Tom Wagner's Forum. Somewhere he said that Norelco Tomato was his best frost tolerant tomato of many. Google failed me on finding any mention of it because of Norelco razors.

I thought if anyone had it, Bill Minkey would, but he doesn't have it listed.

Epigenetics make a lot of sense to me, actually. If a plant is subject to cold temperatures while small, it might accumulate coumpounds or grow in a way that makes it less fragile to cold damage. It's likely a trade-off, the plant will be smaller, stunted growth and all, but would be able to resist cold damage better. While the same clone, in a heated greenhouse, would dedicate all resources to growth, yield. I mean, it's pretty well-known that taking greenhouse plants and bringing them outside without acclimatization will be very stressful to them. Plants grow adapted to certain humidity levels, temperature levels, UV levels, etc., and if grown in a stable environment and just instantly switched to something else, shock and death can occur. I've seen this a lot. And there's a lot of pages on "hardening off" tomatoes.

I'm also convinced genetics play a large role as well, though. Genetics is like owning a winter coat or not, and hardening is getting used to lowering temperatures and thus knowing to put it on before going out.

Perhaps tomatoes could be bred to be frost tolerant without needing to be exposed to cold, but the mechanism for that would probably be an allele that just tells the plant it's cold even when it's not really cold, triggering that cold-response with little to no stimulation, so that if cold does happen, it's ready, even if it had little reason to believe it was coming (figuratively, of course plants don't "think").

My grandfather and I have sown tomatoes in fairly cold conditions (~6C), and other than slowed/delayed growth, they did fine. Frost is another thing, though. I had 1 plant that seemingly survived the first fall frost, a few years back, and it was a hybrid, so the reason it survived while the others of the same variety didn't is possibly non-genetic (though assuming that it wasn't bred from double haploids, that variety could also have had some genetic variation on untested traits such as frost resistance).

One of the nonsensical things that happened in 2017 was a Blue Gold survived a frost with top growth when all the plants of the same variety around it froze to the ground and resprouted. Seed saved for a few generations of consistently harsh springs and I bet epigenetics is triggered. I suspect that is the case with some of the cold hardy varieties. Wouldn't be surprised if plants that resprouted from the ground have epigenetic change too.

Something I think would be kind of cool, especially with an abundance of home saved seed, would be to have something like 90% mortality. In my garden so far no matter my scheme intentional or unintentional: freezing, dry farming, direct seeding, that is a very rare level of mortality. Might have come closest in 2017 with plants exposed to two spring frosts- the earliest I transplanted. I am spending a lot of time and effort trying to get some exotic DNA from wild tomatoes, but perfectly ordinary tomatoes as long as reasonably short season, seem to do perfectly well with everything I have come up with to thwart them except for multiple frosts and my very worst shallow clay soil.

One very ordinary tomato I think would be good for anyone looking to start a grex with would be Sungold F1. It is short enough season to direct seed here. It and its descendants taste good. There is sometimes some exsertion of stigmas so outbreeding is possible. Its an F1 so some variability is already built in. 

With the wild x domestic hybrids I have had 90% non-reproduction before. Though the plants survive they just don't set fruit. That may be the case again this year as its an F2 and the two breeding systems seem to have complex incompatibilities. In 2018 I think I had one of a dozen F2 hab crosses produce a fruit and one of a dozen F2 penellii crosses produce a fruit. I planted more plants in 2019, still had a lot of infertility in the penellii. My solution to that for 2020 will be to plant much larger numbers of seedlings this time. That was basically just selecting for fertility though.

Quickly looked through my seed box, and look at that: [Mountain Magic 2017 (frost resistant?)]

If I'm looking at my archives right, a first light frost occurred on the 12th of October 2017, and a killing frost occurred by the 25th, and by then only 1 plant still looked alive and it was one of the Mountain Magic plants (the other Mountain Magics, Defiants, and Plum Regals had perished).

Got a bunch of seeds, 100 or so probably. Guess I'll be sowing that this year.

Wow. I tried Startpage and excluded -razor -nose -beard -philips, and still got five pages of nothing. Maybe nobody is breeding it? But I should think there would at least be a mention of the variety.

Or Tom never released it to the general public.

http://tatermater.proboards.com/thread/416/resistance-cold

Here is the link (above) where Tom said it.

I still have saved seed from 2017's lucky/potentially epigenetically changed plants like a mixed envelope of blue gold from both plants that resprouted and the one that didn't need to resprout. I have less need to grow Blue Gold now that I have my own shorter season blue skinned bicolor started so probably won't plant it again this year.

I wonder what it takes to trigger those epigenetic changes and keep them triggered. Is it enough to live in a colder climate and save and start your own seed? Does direct seeding help? Do varieties that consistently volunteer year after year get the local epigenetic changes locked in? Or does it only happen in particular climates or in particular years?

Over on tomatoville Lee Goodwin of J and L gardens posted this on the http://www.tomatoville.com/showthread.php?t=25599&page=9 interesting breeding possibility thread Darrel started.
"I'm continuing with this project, now working toward tomatoes grown in unheated hoophouses for the early market. At this point I have several S. habrochaites crosses with good cold-tolerance (down to 25-28 F several nights in a row). Two also have excellent fruit set and flavor. They are both large cherries, shown below. I plan to slowly increase the size by crossing back to Sasha's Altai or others like LA3969, 0-33, and I-3.
I also requested some seedstock from GRIN which should arrive shortly. It includes high brix lines, two more accessions with the (sucr) trait, and a few ultra-early strains like Beaverlodge 6714."

That strongly suggests that breeding with LA 1777 has some possibilities for this. I have purchased packets of Lee's new Wild Child and Weight in Gold varieties to try in 2020. Very cool work I am intrigued. Though will probably only grow one plant or clump of plants to try them.

Lots of LA1777 in the background of the promiscuous tomato project. Will be interesting to see what crops up there in the way of cold and frost tolerances. Also they've been grown for generations in Josephs and now my conditions. So should be well on the road to adaptation.

It's possible he misspelled or misremember the name, and that Norelco is not the right name.

As for epigenetic, could be a lot of things. Exposure to freezing temperatures while a seed. Exposure to freezing temperatures while a seedling. Constant exposure to freezing temperatures. All of these, but with cold instead of freeze?

There will probably be some physiological barriers that are harder to overcome than others. In most trees and shrubs, flowers and floral buds are the least hardy part of the plant. Getting a plant to resist freezing might still not mean that its flowers/fruits will survive under 40F. "Cold resistance" molecules might not distribute evenly within the plant.

How does the supposed frost/cold tolerance work, anyways? Some species will fight cold by generating heat (i.e. skunk cabbage).  Some species will fight nucleation of ice crystals by modifying their internal solutions so as to lower the freezing point (ex. increased sugar content in quinoa, supercooling). I suspect some resist by modying their susceptibility to cell burstage due to freezing. Glycerol can be added to a yeast solution to prevent crystal formation (is this another example of supercooling?). I can't give examples, but it's possible that some species may be able to insulate themselves, to offer minor protection from cold/frost (though given how thin plants are, this effect is probably going to be extremely minor at best).

It's known that brassicas respond to frost by sending sugars into their leaves. I'm no expert on the subject, but I'm getting the impression that storing sugar into leaves is the main form of frost tolerance in plant species. By extension, testing tomatoes for higher sugar content in their leaves would possibly work as a proxy for frost resistance, and measuring sugar content following various treatments (seed exposure to frost/cold, seedling exposure to frost/cold, plant exposure to frost/cold, non-exposure to frost/cold) would probably be able to give hints on the underlying mechanisms.

Tom replied on his forum. Called it notelco this time, but says he isn't releasing it.

https://www.nytimes.com/1977/05/14/archives/upstate-scientists-is-trying-to-breed-a-tomato-that-can-stand-the.html

This article from 1977 is something I found awhile back But had lost. It's an interesting bit of history on cold/frost tolerance breeding.

Quote from: William S. on 2020-02-17, 08:40:18 AM
That strongly suggests that breeding with LA 1777 has some possibilities for this. I have purchased packets of Lee's new Wild Child and Weight in Gold varieties to try in 2020. Very cool work I am intrigued. Though will probably only grow one plant or clump of plants to try them.

Interesting, i wonder the fruit size of "Weight in Gold". The description says nothing about it. Any clue ?

I don't worry much about frost tolerance in tomatoes cause my season is plenty long, I don't need to. But I do have a lot of volunteer tomatoes both in late summer and early spring and I see definite differences in them as far as tolerance goes. A later frost may kill most but not all of early volunteers and similar thing in the fall. Of course the fall volunteers all end up frozen eventually but some last considerably longer than others.

I often keep some of the spring volunteers, wonder if I accidentally selected for tolerance. I never tried or looked for varieties with cold tolerance mine are all pretty generic by plant breeding standards. I reckon cold tolerance if there is any would about have to be epigenetic.

Quote from: Nicollas on 2020-02-18, 04:09:17 AM
Interesting, i wonder the fruit size of "Weight in Gold". The description says nothing about it. Any clue ?

Yeah, small is my guess from what Lee said about them on tomatoville.

I worry more about late Spring frost than early Fall frost, personally. Gardeners around here like planting their stuff much earlier than they should, and even if one waits, frosts or near-frosts do occur in early June. I don't mind waiting 'till the first of June, personally, but waiting for the 8th is a bit too much. :P

Quote from: Dominic J on 2020-02-18, 07:52:22 AM
I worry more about late Spring frost than early Fall frost, personally. Gardeners around here like planting their stuff much earlier than they should, and even if one waits, frosts or near-frosts do occur in early June. I don't mind waiting 'till the first of June, personally, but waiting for the 8th is a bit too much. :P

2017 was a fairly early spring here but I got a little overconfident about long term 15 day weather reports and planted early. Thus everything got frosted and some things got frosted twice. Also direct seeded seeds germinated early enough to get frosted a little

2018 I waited till closer to average last frost here of May 15th and no frosts.

2019 was a very late spring but I still set everything out around May 15th and there were no more frosts. Volunteers responded to the cool weather and came very late- after all danger of frost was past. Peruvianum did not volunteer until it was too late to set fruit. I think it needs a decent rainfall event or something to prompt germination.

It is possible to catch a late frost here even into June. Though I also know now from 2017 that many tomato plants will resprout- though it may be worthwhile to bury them a bit deeper when out planting.

So to flirt with spring frost I really need to set things out early- maybe even late April. Not really planning on doing that this year.

2020 valley floor winter precip is low especially in the form of snow- I expect no vernal pool this year, unless we get drastic snowfall again in March. Could be heading towards a warm or at least dry spring.

So if you are out planting June 1st and should be June 8th. Then frost tolerance might be plenty useful for you!

Though there has been talk on the other forums- it perhaps only works with dry frosts without dew.

Dew is said to help plants resist frost, though, isn't it? That's why strawberry growers will occasionally irrigate their fields in the case of frost, to help protect the plants.

http://www.omafra.gov.on.ca/english/crops/facts/frosprot_straw.htm

When do you typically sow your tomatoes, and what caliber plants do you typically plant outside in the field?

People around here seem to like to plant their stuff around the 21rst of May, which in my opinion is too early. It is pretty frequent that it freezes at least once after the 21rst, or that near-freezes on bought nursery plants will otherwise pretty much damage them beyond repair. The only June frost I remember was in 2015, and not every region actually froze, some only dipped to 2-4C or so, and that was around the 6th of June if I remember correctly.

I think I'll be trying some chill tests on my seedlings from my 2017 late frost Mountain Magic survivor. I've got a few small fridges that aren't serving any purpose, I'll just stuff the seedlings in there. Not sure how cold I can make them go, but I can also stuff them in my spare freezer. Though unless I buy myself an inkbird, even at the warmest setting, the freezer is probably going to be too cold. There's always the option of just stuffing them outside when the temps are around -1C though. Cheaper and simpler. :P

"When do you typically sow your tomatoes, and what caliber plants do you typically plant outside in the field?"

It has been changing. I'm in school again for a teaching certificate and spring break is about 6 to 8 weeks before may 15th which is the expected date of last frost. So transplants usually get started at spring break. Plants are whatever size they get to by may 15th and if the weather reports are good I pop them in the ground and walk away.

Direct seeding I think it would be fine to plan for germination to start as early as ten days before last frost. So plant 20 days before expected last frost. This is when I would plant if I wanted the direct seeded seedlings to have a chance of flirting with frost.

In 2017 the first year I tried it I planted one small dense block direct seeded in March. Most of them were an inch high for the last frost and most of those survived. A few varieties seemed more susceptible. Being close to the ground may have some advantages.

In 2018 and 2019 nothing came up or volunteered till after last frost.

May 15th is also fine for direct seeding here. I would not expect these seedlings to have a high chance of flirting with any frosts. Though it's possible, just rarer.

Tomato seeds seem to have a fairly decent self regulation system when it comes to germination. I had some really decent big 1" rainfall events in 17 and 18 with good timing. I think that is why the peruvianum didn't germinate at the proper time in 2019. There wasn't a large enough rainfall event at the proper time. Temperature wise they seem to wait for reasonably warm temperatures. Some years like 17 fake that out a little. Other years like 19 it doesn't get warm enough to germinate till after all risk of frost.

I put some tomatoes out earlier. Big Hill x W4 G2 and they survived but are far worse off than the ones that stayed warm.

I should really dig out my notes so I can talk about it more scientifically,  but something I learned / confirmed in my genetics class last semester is that epigenetics and genetics ARE linked like i thought. Basically there is a phenomenon where epigenetics will use methyl tags to silence genes not being used. Every time the normal DNA enzymes go to copy that DNA there is a certain chance that it will skip over it and that silenced gene will be left out permanently. The more times epigenetics has silenced the same gene over and over and this process happens over and over I figure the statistical likelihood goes up that is will transition from epigenetic to genetic.

So the basic takeaway is yes, epigenetic changes caused by the environment can eventually (over many generations if left in the same environment) cause permanent DNA changes.

On March 8, I sowed tomatoes directly into the bed. ; My own line, some old seeds from plants with which I started breeding years ago and some Ph 2 and 3 lines.
My own and the old seeds have sprouted, still very small, none of the Ph2 and 3 lines yet. My lines seems to have potential.
There have also been night frosts in the past few weeks, but I'm not sure whether they had already germinated back then.

Not breeding per se, but grafting tomatoes on cold tolerant S. habrochaites LA1777 improves growth at sub optimal temps


https://www.sciencedirect.com/science/article/abs/pii/S0098847208000117

LA 1777 is an important progenitor of the promiscuous tomato project.

Quote from: Nicollas on 2020-02-18, 04:09:17 AM
Interesting, i wonder the fruit size of "Weight in Gold". The description says nothing about it. Any clue ?

Weight in Gold didn't produce for me in 2020, but not enough plants to know for sure if I can't grow it. Wild Child very productive red cherry notably early.

Quote from: William S. on 2020-05-15, 07:15:36 PM
I put some tomatoes out earlier. Big Hill x W4 G2 and they survived but are far worse off than the ones that stayed warm.

Eh they were all wild type.

Quote from: ImGrimmer on 2020-05-16, 03:14:31 PM
On March 8, I sowed tomatoes directly into the bed. ; My own line, some old seeds from plants with which I started breeding years ago and some Ph 2 and 3 lines.
My own and the old seeds have sprouted, still very small, none of the Ph2 and 3 lines yet. My lines seems to have potential.
There have also been night frosts in the past few weeks, but I'm not sure whether they had already germinated back then.

After slugs had killed almost all the seedlings, the remaining seedlings only started to grow in June. Before that they were only a few centimetres tall.
This is what they looked like later on.
Many different fruit shapes and also different blight tolerance.


(https://live.staticflickr.com/65535/50739761257_fddc7f95fe_z.jpg) (https://flic.kr/p/2kiGxgX)
(https://live.staticflickr.com/65535/50738918263_6173186afa_z.jpg) (https://flic.kr/p/2kiCdFz)

To the best of my knowledge, the epigenetic cold tolerance is induced by exposing seedlings to cool temperatures during the first 6 weeks of life.  The method was posted by Ami at TV, and a long thread about it.  There are lots of variations practiced by growers, depending on your ambient conditions, which all seem to work, to bring out the cold tolerance in the tomato (if epigenetically present).   Some non-cold tolerant varieties can be stunted or non productive if treated this way though.

I am not surprised that your seedlings stayed small until temperatures warmed up.   I spent some years pushing the envelope to try to get earlier fruit.  In the end though I concluded it wasn't worth it to push back beyond a certain point.  You simply spent more time trying to protect the seedlings or monitoring and worrying about them, for the sake of a very few, often substandard quality, early fruit.  Main crop production was never earlier than the temperatures permit, even if you do get to celebrate "earliest fruit" it's hardly worth the effort.  Even if you did nothing extra beyond the daily care, you add to the labor by planting too much earlier and get very little value in return for the extra days.  IMO the best strategy is to know your own climate or growing situation well, plant at optimal time to aim for 'earliest main crop' and forget about the early outliers.

Yeah almost all of my tomato seedlings have deep purple / red stems, deep red veins on the cotyledons. Basement is always a bit colder than I would like for seed starting - winter / very early spring. Temperatures have been getting higher though. Suppose the seeds from these tomatoes will be nicer next year.


I mentioned that I was starting some Pimpinellifolium, Neandermato, Saraev M-22, Purple Smudge, Double Rich, Burnley Bounty - some other potentially cold tolerant wilds in another thread. I will probably make crosses with these using Big Hill. If any of them are able to tolerate cold temperatures / continue flowering / growing - I will make sure to grow the F1 indoors bonsai style. Or outdoors if both parents are early enough.

Purple Smudge - Double Rich - Burnley Bounty are all descended from Solanum peruvianum. Unsure if they are from the same accession though. Most of these are said to be fairly cold tolerant.

From what I have been reading, Burnley Bounty only flowers / fruits later in the season. Assuming its a trait inherited from Peruvianum. So earliness is probably out for that one.

Double Rich was bred mainly for North Dakota which is zones 3 - 4. Double Rich isn't mentioned to be cold tolerant on any of the sites selling it - but the primary breeder focused on cold tolerant / early tomatoes. Can't really find any sites with reviews of it either. I suppose it isn't a commonly grown tomato. I found a review on Youtube mentioning that it was fairly prolific, sweet. Some websites mentioned it is early - good for short seasons. I will have to test for any possible cold tolerances myself...

Multiple websites have mentioned that Purple Smudge may have a different gene responsible for the purple coloration than other Purple tomatoes. Also supposed to be pretty hardy.

I found some old discussions when researching a bit more about Purple Smudge, mentioned some other cold hardy accessions:

LA3969 is supposedly a very cold hardy habrochaites introgression line. Assuming Neandermato will work well enough to recreate a line like this.

LA2006 can apparently set fruit at 40F. Hopefully I can find something similiar with the pimpinellifolium types I am trialing.


I will post results later on in the year.

Darrel Jones (Fusion Power on some forums) is the source of the info on some of those lines particularly LA3969. He bred a tomato called Tastiheart that he said has good general resistance to cold and is crossing it with LA3969 he reported in October 2018 on the homegrown goodness forum that he is at least four years out on a release. Guessing that means at least the 2021 and 2022 growing seasons left.

Quote from: Joseph Lofthouse on 2021-03-24, 11:33:46 PM
Hmmm. I was still keeping records in 2016.

I think that the plant with the huge flowers, that survived for 2 months after the other tomatoes had died was LYC2568. It also sailed through the spring frost tolerance trials. Definitely not LA1777, which is a delicate plant. If I were to restart this project, I wouldn't use LA1777. I would choose one of the accessions with huge showy flower clusters.

I think that photo of that plant of LYC2568 Joseph took of the plant he grew was one of the most inspirational to me.

I haven't yet replicated that success with habrochaites in my own garden. I suspect a larger grow out of Neandermato would be needed. Joseph has sent me plenty of Neandermato seed so maybe next year I'll do that if I remember.

Quote from: William S. on 2021-04-05, 09:50:08 AM
Darrel Jones (Fusion Power on some forums) is the source of the info on some of those lines particularly LA3969. He bred a tomato called Tastiheart that he said has good general resistance to cold and is crossing it with LA3969 he reported in October 2018 on the homegrown goodness forum that he is at least four years out on a release. Guessing that means at least the 2021 and 2022 growing seasons left.

Yeah I have been reading Darrel Jones, Tom Wagner posts on other forums. Lot of the topics are old, but still interesting to me.

On the Purple Smudge portion, Darrel Jones mentioned all sorts of other fun things.

Neandermato is a mix of all sort of different habrochaites accessions. I am separating my bunches pretty soon. Not a huge grow out, that will be next year. Should be able to attempt some crosses using it though. The pimpinellifolium that I grew last year still had flowers on it in the 40F range. No fruit set though. And it stopped putting on new growth.

My habrochaites probably survived longer due to my lack of watering. The taproot went down pretty far into the ground for water. Probably protected it from a bit of damage. It was a glossy leaved type. I have no idea what accession it was... It died at around the same temperature range as LA 1777 usually does for others.

The F2 should have some exerted types that I can use to mix with Neandermato.

Probably won't be seeing Darrel Jones tomato for quite a while.
Working with wild species such as LA0417 takes more time than usual. I've got several breeding lines going with this background genetics. LA0417 churns out very good disease resistance to foliage diseases. In the cross with Tastiheart, I got an intense red color. I know in advance that stabilizing this into a viable tomato line will take several generations and may require a cross to another large fruited tomato before it is worth releasing.


Assuming that the LA3969 - LA2006 - Domestic cross will take just as long considering he wants a fully stable cold hardy tomato with decent sized fruits / cold / disease resistances.

Another quote from Darrel Jones.

Domestic tomato originated in the lowlands near sea level along Peru's South American coast. It has very little cold tolerance. Solanum Habrochaites originated in the highlands of Peru and Ecuador at altitudes up to 3600 meters. It has significant genetic cold tolerance. Introgression lines were developed with domestic tomato by Tanksley and Monforte. LA3969 shows the most cold tolerance with a large habrochaites introgression from chromosome 12. Another cold tolerance locus is on chromosome 7.

Tomato, like most plants, transports nutrients up the stem and photosynthate downward. Rubisco is disabled by free radicles about 45 degrees and the plant goes into temperature induced shutdown. LA3969 does not go into stem shutdown at 45 degrees and recovers much faster from very low temps.

Earlinorth tomato has the ft gene which enables fruit set at 40 degrees F. I've got some breeding material that combines LA3969 with Earlinorth. Sub Arctic Plenty is a commercially available tomato with exceptional cold tolerance. I also have Tastiheart which has survived temps as low as 22 degrees. Note that surviving 22 degrees pretty much means the plant lived, but it was a mess for about 3 weeks until settled warm temperatures got it back to growing.

I can't find any sources for Earlinorth tomato - probably have to request it from somewhere. Sub Arctic Plenty apparently has good cold tolerance. Wish I bought Sub Arctic Plenty seeds to compare with other cold hardy tomatoes...

Looked into Earlinorth a bit - parents are Farthest North and Polar Circle tomato. Couldn't find Polar Circle seeds either.

Earlinorth was used in the breeding of some other tomatoes though. https://cdnsciencepub.com/doi/pdf/10.4141/cjps72-018
Sub Artic Plenty is one of the children mentioned here.

Darrel Jones also mentions that Sub Arctic Plenty, Sasha's Altai, O-33, Earlinorth, and PI120256 are pretty cold hardy. I will try some of those next year as well.

This is the two week window here to really flirt with frost if I want to, I have one tray of regular leaf blue bicolors that I want to discard. Might plant them with a chance of "areas of frost" Monday morning. Though I don't know if it's worth it as it's not intriguing genetics. They do have a good chance to be the F4 descendents of a Blue Gold that weidly survived a frost. If that was epigenetic this could keep it going.

I think my stuff might be extra blue in stem and leaf this year because the basement tomato station is a bit cold.

Survivors from recent frost with least leaf damage.

XL red strain of promiscuous project 4 small seedlings
Great Big Blue one small seedling     
Sungold F4
Amethyst Cream one very small seedling
F3 Big blue bicolor with spots

About half or more of the uncovered promiscuous bicolors got wiped out. The rest look great. Some of them were in deep sand addition. All were in the best positioned of the planted gardens for frost.

The covered S35-37 and R18 and a couple of promiscuous bicolors did pretty well. One uncovered plant did ok. One plant got hit mediun hard the night before.

Deeper sand seems to enhance survival. Probably holds and radiates heat.

Small plants seem more likely to survive.

Fields close to the bigger hill seem harder hit- best gardens are on the slight rise after the dip. Dip is the worst for frost.

Additional plants varied and some look like the stems survived and may resprout higher up. If memory serves small plants do not resprout well. Uncertain how many will really survive of those that look harder hit.

Genetics wise this frost event does make me a little hopeful for the frost tolerance potential of the promiscuous project simply because there is apparent variation in susceptibility. Though potential confounding variables abound.

Quote from: William S. on 2021-04-30, 11:06:53 PM
This is the two week window here to really flirt with frost if I want to, I have one tray of regular leaf blue bicolors that I want to discard. Might plant them with a chance of "areas of frost" Monday morning. Though I don't know if it's worth it as it's not intriguing genetics. They do have a good chance to be the F4 descendents of a Blue Gold that weirdly survived a frost. If that was epigenetic this could keep it going.

I think my stuff might be extra blue in stem and leaf this year because the basement tomato station is a bit cold.

Only one Blue Gold descendent survived the frost event with good looking foliage. I suspect no superpowers but just random chance there.

Glad to hear you got some survivors. 
Even though it's hard to disentangle random chance, micro-environment and other non-genetic factors, the individuals that survived may carry forward the 'event memory' as a tweak on gene expression.  Or who knows, it may even affect the 'shuffle' when segregating. 

The state of the roots seems to be a big factor in cold event survival.   Wet roots do worst, in my experience.  The sandiness that you mentioned, might be a factor if those roots were better drained. 
Also I've noticed that end of season adults with full root systems will sprout again after the tops have been killed by hard frost.  So it's interesting that you noticed smaller plants having better survival.  I wonder if those phenos put more energy into growing the root system before investing in the tops.
I have encountered a few vars that are like that - Zolotoe Serdtse is one.  You can't force them to bud in a small pot, and they don't put on top growth as soon as you plant out.  They want that volume of roots before they will invest. 
I wonder if root vs shoot investment is part of the strategy employed by wild tomato relatives.
I suppose it could be investigated by growing in clear containers.

Quote from: William S. on 2021-05-22, 10:40:38 PM

Deeper sand seems to enhance survival. Probably holds and radiates heat.

Small plants seem more likely to survive.

I would think it has more to do with sand draining faster and thus less water. When cold hits its usually the water that kills.

Younger plants do seem to do better of any crop.

Dar Jones still has some very cold and frost tolerant tomatoes.

https://growingfruit.org/t/talking-about-tomatoes/26543/42

QuoteYes, but have to clarify that tomatoes are NOT frost tolerant meaning that they are susceptible to frost forming on the leaves and that is true for all wild species. It is possible to select for cold tolerance which really breaks down to a group of genes that code for improved transport in the stem of the plant at low temperatures. These genes mostly come from S. Habrochaites which is arguably the most cold tolerant of the wild species. LA3969 has most of the required genes. Cultivar Earlinorth has the ft gene which permits flowers to set fruit down to 40 degrees F. Of the varieties you can easily find that exhibit excellent cold tolerance, several are from Russia such as O-33. Siberian is one of the easiest to find. Tastiheart is a variety that I accidentally selected for cold tolerance back in 2007. Tastiheart can handle temps down to 22 degrees F if you drop a cloth over the plant to prevent frost forming on the leaves. LA2175 is the best of the pure S. Habrochaites lines I grew for cold tolerance and has excellent foliage disease resistance.

In 2017's frost event I planted out very large plants and many resprouted. Last year end of the season plants were resprouting. Tried to cut and reroot some resprouts.

I expect additional survivors from resprouting both stem and base but do not expect smallest plants to resprout. Some completely lysed down to the ground and collapsed. Others still have significant stems that look ok. This list is of plants on the cold field that look ok with leaves intact.

The 30F met the dew point otherwise not. That means some plants may have stayed dry. Apparently a wet frost is harder to survive from things Dar Jones has said. All the fields were unwatered yet this year so dry as it's been a dry spring.

The plants I did cover lost the tip on some where the cover touched.

Small plants comment also mainly pertained to the coldest field.

I have seed for 0-33 and Tastiheart. Did not grow it this year as did not intend to explore frost this year particularly. In 17 I
think 0-33 succombed as did the Russian strains.

2017 also was remarkable in that tomato seed germinated by May 5th meaning ten day old seedlings survived frost on May 15th. Every other year including this one, no germination has occurred until after last frost.

I wandered around the gardens today flagging surviving tomatoes. Quite a few survivors really, I counted 23 in the hard hit slushy garden.

One that caught my attention was one F4 Sungold survived
with nothing obviously different from the rest of the clump. Though I've seen similar things with non-segregating varieties. Why does one tomato collapse to mush and the next look untouched on occasion ?

Then when I got home the weather forcast changed to 36 F that could easily drop down to freezing. I planted more today including the irreplaceable LA2329 growout thinking it was finally safe. Will take my chances I guess.

Found a lot more resprouts yesterday. Interesting. Wonder if it does cause epigenetic change to freeze to the ground and come back? This is basically the second time in five years.

I'd be pretty sure it causes epigenetic changes, at minimum.
The second question is, do these events affect the chances of transposing elements etc when the time comes to set seed.  It stands to reason, if you need to adapt to extremes then shuffling the genes in less usual ways would be an adaptive response.  Especially for an inbreeding species.

My Mission mountain sunrise bicolor tomatoes are descended from a 2017 frost survivor Blue Gold and a unknown potato leaf from Joseph's old mostly red landrace. They seem to have a lower response about 1/2 than Exserted orange. Exserted orange was supposed to be hab x big hill but came out just orange and seemed fully domestic, though a common source of orange is sun gold F1 and it has one F4 or so that survived this frost. By response I mean either surviving with top growth intact, stem intact, or resprouting from the base.

The variety Bosque Bronze seems to not be resprouting so far. Looks like stem was largely intact- no collapse, but no new growth yet. May just be too soon.

Some plants were just to small to come back.

Some got lucky microenvironments and survived.

The resprouts though are just good resprouters but that is a lot of stress.

Wondering if I could / should make 2022 about cold /frost tolerance.

One thought is to do a big habrochaites grow out and deliberately plant them to soon maybe in a couple waves starting at the end of April. To ensure a frost trial.

Joseph had that methodology where he would half freeze a seedling tray with a tomatillo control and keep the survivors.

Aha that is a clever method, takes away the microenvironment variables so what you get is selection for frost tolerance.

OTOH your field trial is totally relevant to the specific conditions, including the soil, microenvironments, frost, heat, etc.

Refrigerator, freezer, and growth chamber space would be really cool. Hmm I know of a refrigerator that is often empty that time of year where I might be able to stick a tray.

The seedling method is good because you can have a very dense population in a small space.

In the field it's really kind of a mess. I have the urge to rototill it (wont) because of the perennial weeds Cirsium arvense and Cardaria or Lepidium draba

62 survivors in my slushy field.

I think in my slushy field I lost just Terrior strain galapagos tomato, 42 days, Bosque bronze, chariot f3, wild child, and weight in gold. That I found today anyway. Replanted a few things today. Had some leftover regular leaf bicolors from the Mission Mountain sunrise project since I decided to make that Potato leaf.

https://phys.org/news/2021-06-crispr-highly-efficient-gene.amp

They used tomatoes amongst the experimental crops.

Highly interesting because it seems we can now just manipulate epigenetics directly.

I do like his attitude about bringing out the positive potential that's already present in the plants.

OTOH, the existence of adaptibility or "free will" in plants, which allows them to choose a strategy for survival depending on circumstances, seems somehow more important to me than the opportunity to manipulate their genes and switch something on permanently which could be disadvantageous in an extreme environment.

Just for example, I noticed this year of alternating extremes of heat and cold (as I have in some times past) that virtually all of my tomatoes chose to fatten up a first fruit to near maturity, before growing up any of their other first cluster sets.   This is not ideal for me as an animal that hopes to eat a full truss of fruit.  I would rather see every set growing up progressively as new ones are made, even if it means that they are all smaller for the usual growth period, instead of one large fruit hanging there precocious to the others.    I was relieved to see at a certain point that the deferred fruit started to grow and fill up the truss.  But those first fruits which were fattened at the others' expense will be ripe long before them.

I don't know exactly what triggers are involved, that produced this reaction in the plants, and if it had been up to me to decide, I would've had them working on the full truss at once.   This is the kind of thing that could probably be switched on permanently, and prevent the plants from choosing to do otherwise in any circumstance.

So think about the advantage that they got, in devoting their early energy to a single fruit.  In a disastrous year of extremes, this strategy ensures the best chance to mature seeds.  Suppose the extremes of heat and cold continued or got worse, the first fruit might be all that they had a chance to ripen.   It would not feed me, the animal, for that year, but it would produce viable seeds for the next. 
And if my disappointment at getting a single fruit would be bad, think about getting none at all, and no seeds, because the fruit were all too small and immature when the worst case scenario came along.

The ability to switch on some epigenetic features permanently is, in a sense, no different from switching something off, if indeed you remove the possibility for the plant to choose which state it should be in, depending on circumstances.

Quote from: William S. on 2021-05-29, 09:30:08 PM
I wandered around the gardens today flagging surviving tomatoes. Quite a few survivors really, I counted 23 in the hard hit slushy garden.

One that caught my attention was one F4 Sungold survived
with nothing obviously different from the rest of the clump. Though I've seen similar things with non-segregating varieties. Why does one tomato collapse to mush and the next look untouched on occasion ?

Then when I got home the weather forcast changed to 36 F that could easily drop down to freezing. I planted more today including the irreplaceable LA2329 growout thinking it was finally safe. Will take my chances I guess.

William,

Can u tell something about the serigation of the Sungold F2 plants and later generations?

Roland, in my experience Sungold leads to orange tomatoes a lot like Sungold but a little more variable in size and flavor. Sungold and descendents can be a little bit exserted and can outcross. I would consider a red to be an outcross. It has never been a major grow out for me so inadequate data.  Though I suspect you could take Sungold F1 as decent germplasm for early and tasty tomatoes and then select for preferences you might have. There are lots of dehybridizations on the market.

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. 

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.

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?

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.

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.

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.

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.

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.

LOL William.  Such self discipline.  8) ::) :D

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?

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.

My Sungold F1 has exserted stigmas.

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.

"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?

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.

Quote from: Steph S on 2021-07-06, 08:02:43 PM
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.

Don't suppose the flower here could be Apricot? Found it on one of my mix of F1 pimpinellifolium crosses. I think there were a few others like that. They are all dead now though.

Also posting a strange flowering - whatever it was. The plants with these small buds eventually formed real flowers.

I am going to recreate my initial cross with pimpinellifolium - habrochaites. I am assuming that I had some variation in the F1 because I used over 30 fruits - and their seeds, screened for anything off-type from the parent. Being different species, I could have lost initial genetic information in that original cross due to only saving seed from a few F1 crosses... Next time I will grow most of the hybrids outdoors where I have room for them.

Also, if I can reproduce the white flowered types, that would be pretty nice.

(Suppose I got everyone a bit off topic!)

Wow Garrett, those are truly gorgeous.  8)  Very cool.  There are pics of apricot flower type at TGRC if you want to compare.
That habrochaites anther color is also really pretty.  :)

Guessing genetics by flower color is a little tricky, because the color changes as pollen matures and is shed.  So you need to look at flowers in different stages.  When I get a chance I'll start a thread and try to get some decent pics to show the recognizable types that I know.
The tangerine orange anther cone is a deep orange color as soon as it opens. Petals start yellow but then fade peachy pale orange as they begin to age.   
Flowers on beta, red, bicolor or pink fruited start either a warm yellow or light orange that quickly deepens to orange as pollen matures and is shed.
Flowers on yellow or gf (black or brown) fruited start a greenish yellow but may also turn a warmer yellow to orange from the pollen being shed by the time they're done, however that is slower than the development of orange color in the red or Beta type.

If the orange in your habrochaites crosses is tangerine, that could also turn up unexpectedly from non-orange parents because of t being recessive and not expressed at all as t/-.

The conclusive way to determine if Sungold is Beta or tangerine, would be to cross it to a red and a yellow fruit and check the progeny: In a red cross, F1 Beta will ripen orange-red, and 3/4 F2 will be expected to be orange or orange-red.   F1 tangerine will be just red, and the 1/4 ratio expected for orange fruit in F2.  In a yellow (or bicolor? afaik) cross with Beta, you should get no orange in F1 or F2, while tangerine will show up as yellow-orange or light orange in F2 at the 1/4 ratio.

Very interesting hypothesis that the orange of Sungold Beta is carotene.
The orange in the flowers in tangerine is indeed missing.
I have already made the cross between Sungold and Sungreen. Sungreen is a green tomato and contains yellow(rr) homozygous.

I can make another cross with Sungold x Dorada (Yellow), Sungold x Clou (Yellow) or sungold x Sunviva (Yellow) and of course another cross with a red tomato.

The F1 with a cross of a yellow tomato will possess:
Sungold RR,BB x Yellow rr,--
Rr,B- and yet also show Red and Beta. As a result, I think the phenotype of SunGold x yellow tomato should also be orange?

Indeed, Roland, I don't know if Rr is enough for the B/- to show up.  Look forward to hearing your results.

Quote from: Steph S on 2021-07-07, 06:37:52 AM
Wow Garrett, those are truly gorgeous.  8)  Very cool.  There are pics of apricot flower type at TGRC if you want to compare.
That habrochaites anther color is also really pretty.  :)

Guessing genetics by flower color is a little tricky, because the color changes as pollen matures and is shed.  So you need to look at flowers in different stages.  When I get a chance I'll start a thread and try to get some decent pics to show the recognizable types that I know.
The tangerine orange anther cone is a deep orange color as soon as it opens. Petals start yellow but then fade peachy pale orange as they begin to age.   
Flowers on beta, red, bicolor or pink fruited start either a warm yellow or light orange that quickly deepens to orange as pollen matures and is shed.
Flowers on yellow or gf (black or brown) fruited start a greenish yellow but may also turn a warmer yellow to orange from the pollen being shed by the time they're done, however that is slower than the development of orange color in the red or Beta type.

If the orange in your habrochaites crosses is tangerine, that could also turn up unexpectedly from non-orange parents because of t being recessive and not expressed at all as t/-.

The images that I posted were of my F1 habrochaites x pimpinellifolium. Sadly no longer have them - had too many pots, thinned a bunch of plants out and used them to obtain F2 seed for this growing season.

The F1 types were columnar in terms of growth.

The white flowered type only had that color on a single plant, I used two wild species - wasn't that fun to manage / tie up a stick.

Hopefully I will find the white color again. Along with any other fun genetics.

The F2 plants will probably have a wide mix of different fruit colors. Should be fun.

SunGold F1 is giving a lot of pollen. About 10 times more as my domestic tomatoes.

Today I made the crosses:
Sunviva (Yellow) x Sungold F1
Dorada (Yellow) x Sungold F1
Clou (Yellow) x Sungold F1
Primavera (Red) x Sungold F1
Read Pearl (Red) x Sungold F1
Sungold F1 x Sunviva (Yellow)
Sungold F1 x West Virginia 17B (Red beef)

The flowers used had 1 or 2 petals open and I removed the pollen from this.
Is it true that these are still too young for self-pollination?

I didn't see a thread about crossing techniques so I just started one, Roland.  I often use flowers that are just starting to open, as long as the petals still look white I believe the flower is still immature.

Doing some cold tolerant - earliness testing next year.

Burnley's Bounty - Probably cold tolerance from S. Peruvianum, currently have one plant growing, may be able to confirm this year.

Purple Smudge - Multiple accounts of cold tolerance. Might be able to find out this year as well.

Stupicke Polni Rane - Early, ties in well with cold tolerance.

Saraev M-22 - Multiple forums have pointed out that the cold tolerance in this variety is probably epigenetic, I received my seed from J&L Gardens in New Mexico, may or may not have the epigenetics currently active.

Sub Arctic Plenty - I have a single seed left, will try planting it next year.


Ordered Polar Beauty and Polar Star for next year, they probably have cold tolerance (descriptions of both mention being able set fruit in the 40s, there are some other varieties like this).

Both of these varieties were bred for Alaska's climate.

Unsure if these are a part of the same series as "Polar Circle" which was crossed with Farthest North to create Earlinorth - an early cool tolerant tomato that sets at low temperatures.

Darrel Jones mentions Earlinorth quite a bit in his cold tolerance posts / breeding topics.


I have been finding mixed results online on whether or not Sub Arctic Plenty has the ft gene(fruiting temperature gene) or if its just very stress tolerant. Some websites mention that it can set fruit at lower temps.

Also of course going to be looking for some cold tolerant genes from habrochaites wildlings - etc.

I am unsure if S. Peruvianum shares its cold tolerant genes with cold tolerant S. habrochaites cultivars or not. Should be fun to play around with either way.



Probably going to cross the best performing plant with the ft gene with something like Exserted Orange. At the same time I would be crossing things with noted stress or cold tolerance into Exserted Orange as well. Eventually they would be combined into one base. The nice thing about this is that most of these varieties are early enough that I could do multiple generations within a single year.


Going to be screening plants for anything that puts on new growth in cold temperatures as well. By the end of the year things become "blighty". No new growth pretty wipes out the full potential of the other traits if the plant dies.

Exsertion may or may not be selected for. I do want to add/stabilize all of these traits into a Promiscuous population at some point.

Darrel Jones is already working on something similar, figured I could try out my own version.

Species other than S. peruvianum and S. habrochaites have cold tolerant traits.

https://link.springer.com/article/10.1007/s10681-008-9863-6
https://asset-pdf.scinapse.io/prod/2116776415/2116776415.pdf

S. lycopersicoides and S. chilense also contain some cold tolerant traits, seem a bit more uncommon in these sort of topics - though mentioned at times.


S. lycopersicoides branched off from the "Lycopersicon clade" along with S. sitiens quite some time ago. Hopefully, this means that there are some novel cold tolerant genes that could be mixed with already existing traits.

S. lycopersicoides LA2408, LA2781 grow in some pretty cold climates. The species has been recorded growing 3,700 m - which is higher than other tomato relatives (Quoting this from the PDF, this could have changed or be incorrect). These accessions could be exposed to slightly freezing air or chilling from a nearby volcano - the plants are also apparently pretty exposed, which means there isn't insulation from nearby surfaces.

Possibly better than the 25 - 30F minimum survival trait from S. habrochaites, or just as good. The traits might work well together, probably aren't the same due to being from different clades.

S. chilense accessions have been recorded around S. lycopersicoides LA2408, LA2781 but don't grow nearly as high up. (Listed as the Putre Area in the PDF)


I found mention of LA2408, LA2781 from Andrew on another forum - back in 2017. Having cold tolerant genes that perform better than S. habrochaites genes could be nice.


Of course, most S. lycopersicoides accessions don't cross easily with species in the Lycopersicon clade. Doubting that the trait would result in frost hardiness either, could still be very nice.  (The Abg gene is also found in S. lycopersicoides)

Speaking of exserted orange. My 2021 grow out for snake river froze to the ground and resprouted except for one plant that survived unscathed. Then a few plants lost some leaves in August to early light frosts. Just picked a bunch for seed last night. Should get me to the ounce I need. Would be done by now with that if not for the set back.

So I decided to stick one of my flats of promiscuous seedlings from the LA2329 crossing block in the ground as a way to get rid of them after searching for LA2329 hybrids. Some of them have survived three nights in the cold. Prob 50% or more froze the first night. The mother had everything except good flavor. Should I rescue one before it gets down to 24 F tonight for the epigenetics? Or let them go. I think I'll let them go.

So it has been some time and multiple frosts since I planted two additional flats of crossing block seedlings out in the raised bed. They are 99% dead but I was able to detect lots of live but yellowed cotyledens and at least one true leaf still.

My theory on what is happening here is a sort of protective canopy physics. A extremely dense mat of tomato seedlings will have a bit of an understory and that understory has thermal protection. So in a situation like this after several frosts you will likely have some survivors because of the canopy of the plants that end up dying which I think I've noticed with this patch continues for some time. However I don't really want these seedlings to survive because ultimately this is also selection against  early germination and vigorous growth. Hmm.

an interesting result.

You might decide to keep them anyway. I don't know how well it might work in plants, but in school we learned in microbiology that a gradient of antibiotics will select for antibiotic bacteria from scratch, no plasmids needed. Even if it is mostly a canopy survival result, you could in theory be programming the epigenetics a bit. With repeated conditions from this line it's possible you could create a more frost or colt tolerant line.

Up to you. Might be a long shot, maybe it doesn't work as well in higher life forms than in bacteria. Maybe it selects for other traits you don't want. But it never hurts to rethink ones assumptions and even conder it from other angles. Sometimes culling too early can eliminate interesting things from being discovered later. Other times it is just a dead end.

If they survive to the end of the frost period I will. Though I might move them. Interestingly they had a lot of cold exposure before I put them out there. The greenhouse got really cold during a week long cold spell and I did get a small amount of mortality. I did keep a lot of plants that went through that first part which I think was enough to enduce some epigenetic change. .

Also interestingly now is the time in the spring when I have flirted with early outplanting in the past. I think a flat like this would have a really devent chance of surviving if out planted now here. It might only be subject to roughly the same or fewer number of frost events.

I am growing out the Saraev tomatoes I was dissapointed by in 2017. I concluded that if epigenetic change had occurred it had been reversed by subsequent easy years somewhere. Also growing out Tastiheart which was bred by and has survived for Daryl Jones as long as water was kept off the plants by a cloth.

In 2017 some of my direct seeded tomatoes germinated 10 days prior to the last frost and had good survival at about an inch in height with some mortality. This spring I don't think that will happen as the weather would need to warm which just confirms that 2017 was unusual weather as that has not recurred from 2018-2021.

Note: 28 F again this morning.

One of the direct seeded patches the one with promiscuous tomatoes Joseph direct seeded last year germinated before the last frost and survived it at about an inch high, a phenomenon I haven't observed since 2017.

Some of my tomatoes including the Mission Mountain Sunrise had a significant amount of cold exposure early in the season.

In the greenhouse I planted several tomato plants in the ground before the end of cold. One of them Solanum galapagense LA1410 was the most affected and was set back a good deal by it. It is just now recovering- but it is recovering. This makes sense because islands are very protected from cold by the moderating effects of the ocean. Also they are pretty close to the equator.

I am sure that some of the tomatoes in my garden have had exposures over the years that could potentially activate epigenetics. I am just not sure how much that is worth.

I also noticed that in a dense flat of seedlings that the most protected seedlings survive.

I would like to proceed with cold / frost tolerance breeding but feel like it is hard to eliminate confounding factors like microsite within a flat and microsite within a garden. I think that led me to take a pause from it this year- though there is always a little bit of effect from things like planting too early or potentially from late frosts and cold springs. It would be neat to come up with / brainstorm a improved protocol for this.

Ah.... The confounding effects. Always present in plant breeding. Did that plant thrive because it is resistant to blight? Or because it didn't get infected? Is that rye plant 25% taller than the rest because of genetics? Or did a vole die under it's roots, thus providing an extra boost of nitrogen?

Do short stubby tomato seedlings survive frost because they are protected by taller plants? Or because they are closer to the warmth of the ground? Or both?

My general belief is that I can't understand, nor control for, the confounding effects, so I focus on bulk-selection over decades, as my go-to plant breeding strategy.

LOL vole.   :)
Worth mentioning as an aside, that my tall BT emmer from last year is tall, while the short emmer is short, so that at least was a genetic thing.
OTOH I really don't know why I have patchy survivorship among the grains - did frost get through my row cover tatters?  Was rain penetration uneven?  Did wireworms eat the roots?  Oh well...  We're going with the survivors, whether they're "the lucky" or had some genetic edge.

I stopped starting tomatoes too early for a couple of years.  I was tired of seeing first clusters not set for the effort, but then starting late means they get the scorching in July and it's too late to be setting when it gets hot.  I need my tomatoes to set up when it's cool and ripen up when it's too hot to be setting.
So this year it was early again.
Those seedlings got all the epigenetic prompts they need for the season, that's for sure.
It's a crapshoot starting early, because the weather's so unpredictable.  But even so, I think I'm ahead of the game with fruit set and growing before the end of June.  If we hit some heat bumps I could, technically, let them keep on going longer and set up again when it cools off.   I probably won't do that because I prefer to limit the time I spend growing our tomatoes.  If we hit some cold bumps - I'm not a bit worried about that.   These plants spent what, nearly a month with close to freezing temperatures at night and quite a few days not over 60 F or an hour or two at best above 60, while sitting in beer cups. 
The plants I put outside weeks earlier than I would normally dare, are shrugging off the 'nearly frosty' nights.  It's true we have not had a white one here in spite of the threats this year.  Could still happen but...   no I'm not worried.  Minimal protection is enough, because all their epigenetic resistance has been activated well and truly.

I am deeply curious about the work you guys have done, and once I actually finish a couple projects I want to open up some space to try out the OPs you like and the lines you've created.  I would treat them the way I treat mine, which is as much as I can do to bring out the stress tolerance genetics.   Would also be happy to throw you some seeds of mine  to see how the tomatoes that we've trained to the environment here also perform in your trials.

I do think there's a big difference between wet cold and dry cold, also the difference between a cold night with a hot day, and the long bouts of sunless cold days and nights that we get here.  It's no surprise to me that people in different places have different favorites, because they suit that environment and are at their best.
Heat stress is as big a factor as cold stress, if not more, when it comes to tomatoes.   And the response to variable extremes.  Every year I see my plants wilt and freak out when it suddenly becomes hot and sunny with high UV after a long stretch of grey and cold.   Give them a week of sunny weather and they've adapted to that.  But there's no question in my mind, it's not easy for a plant to be ready for both.

I know there are genetics in some plants at least, that respond to all kinds of stress.  The chemistry for stress tolerance just isn't there in tomatoes in the same way.

I wonder though, talking improved protocol, say instead of throwing a whole flat out in the cold, maybe smaller flats or just the outer part of one of those flats with holes so there are less microsites and the physics is more similar for the individual seedlings.

This spring when I was done with my interspecies hybrid search on some flats I tossed them out into the cold and it was definitely the understory in the center of the flat that survived the longest. I think that was just physics.

Another improvement might be to follow a suggestion from Darrel Jones if I recall it correctly. He stressed a genetic difference between cold and frost tolerance as two different goals and suggested refrigeration for cold. He said non cold tolerant seedlings will turn to mush. Cold tolerant will be fine. So maybe just a little community pot in the fridge for a week for say a segregating population? Also maybe some test pots of seedlings of parent or potential parent varieties.

I suspect that Black Strawberry, Lizzano F1, and a number of currant tomatoes are cold tolerant given this weekend's fruit set findings. Kind of surprised there aren't a few more. Might be that they had some transplanting advantage and some cold tolerance. Fridge test would be interesting on them.

Some cold hardiness in S. pennellii

A calcium-dependent protein kinase gene SpCPK33 from Solanum pennellii associated with increased cold tolerance in tomato
 (https://www.sciencedirect.com/science/article/abs/pii/S0176161722002206)

Accession LA 0716 penellii in your article Nicollas. I wonder how widespread this protein kinase gene is in penellii? If the accessions, we have already been using in Joseph's promiscuous project have it or not.

There is so much tomato diversity locked up in the genebanks but there are barriers both to accessing it and to using it because it is a many generations tomato breeding effort to get these things introgressed into palatable lines.

I wonder too. LA716 is usually used because it is SC so easier to study i guess. It has an impressive range of resistances but again maybe just because it is more studied than other accessions of this species.

For the accessibility of interesting germplasms, we should definitely try to do something between us on this board, because we have access to different levels to different genebanks around the world.

I wonder if this particular protein kinase activity might affect the palatability of the fruit (I did not read the full article for details).

Some of the common frost tolerance mechanisms in other plants involve the accumulation of polyamines like 'putrescine'.  Not a flavor enhancement, I would imagine.

Tomato wild relatives are reported to use the same mechanism for drought tolerance, and probably do so for frost tolerance as well:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5809557/

"..one of the strategies used by S. pennellii against osmotic stress induced by salinity22 was the avoidance of leaf dehydration by osmotic adjustment, inducing high accumulation of solutes during the stress period23,24. Interestingly, this adaptation strategy appeared earlier in the time-course of drought response of S. pennellii than in cultivated tomato. The tomato wild species accumulated organic solutes as sugars and the diamine putrescine if inorganic solutes were not sufficient to reduce the osmotic potential"

Maybe that would not be an issue for frost tolerance in young seedlings, but the question in my mind is, would this mechanism kick in later in the season in response to drought or fall frosts when tomatoes are ripening, and would the same solutes accumulate and affect flavor in the fruit?  Maybe not if it has a high brix ie easily accumulates enough sugars for the purpose.  Or perhaps the same mechanisms do not apply to fruit?

Ever since I read about this some years ago, I've wondered if 'putrescine' might have been a flavor in that horrible pimp I tasted (and spit out!).  :P  maybe a dash of cadaverine too.. :o  As they are named for a reason. :(

OTOH there may well be other frost tolerance mechanisms in the pennelli or others, that would be more compatible with developing palatable fruit.

Interesting: I got the S. pimpinillifolium Mexico Midget to test its inclusion on a top 10 list for flavor. First one I tasted was when the weather was still quite cold- a spitter. Later it tasted fine. I don't know about top ten, but a good tomato. So it is very possible that cold grown tomatoes of fine flavor period may just be a difficult row to hoe. I would be very excited to be able to reliably plant my tomatoes a month earlier without protection though!

To be fair, it is really common for tomatoes to produce less than optimal fruit in cold weather.  The enzymes involved in synthesizing flavor compounds as the fruit ripens are non functional at colder temperatures.  This is why tomatoes shouldn't be kept in a refrigerator.  A lot of varieties also produce bad textures in their early/cold set fruit - nasty, mealy as well as low taste. Not to mention catfacing. There are some varieties that do better than others re fruit quality in the cold, so the genetics is there to select something that works.
We also reach a point in the fall when the remaining tomatoes are not going to ripen or produce a nice fruit if left on the vine.  The solution is to bring them in and bag them and let them ripen at room temperature.  That might improve your fruit quality in the spring as well, if you end up with a line that tolerates the frost and sets well but aren't up to par for taste.  You could pick at breaker and try ripening them under indoor conditions instead.

Just wanted to add:  I had to do some reading to refresh my memory about other chemistry of frost tolerance.  Not everything is putrescine! 

some notes:
https://pubmed.ncbi.nlm.nih.gov/34605046/
Cytosolic proline in basal freezing tolerance 

glycine betaine aka tremethylglycine
also an amino acid derivative, " It has a sweet and umami taste. "
https://en.wikipedia.org/wiki/Trimethylglycine

Discovered in sugar beets, but occurs naturally in many others:  wheat, spinach, beets etc are natural accumulators of gly betaine under stress, and it plays an important role in cold tolerance/frost tolerance.
Tomato unfortunately is a non accumulator.

The enzyme choline oxidase determines whether glycine betaine accumulates or not.
https://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2004.02237.

You can actually spray glycine betaine on tomato plants to induce cold tolerance or other stress tolerance.
Sugar beets are easy to grow.  I thought about making a home product for that but basic desire for the plant to just do it for itself, ahem.  Well I haven't been motivated enough to do it yet.  But it might be fun to spray those late fruits or early fruit under cold stress and see if it keeps em going sweet and umami.

-------------------
Here's something useful about pennellii.  I couldn't find anything open about the protein kinase that Nicolas ref'd.  But there is genetic variation in the accessions of pennellii for stress tolerance acylsugars (sweet and umami, perchance?)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6961621/

Candidate Gene Networks for Acylsugar Metabolism and Plant Defense in Wild Tomato Solanum pennellii[OPEN]

https://wildmountainseeds.com/product/heirloom-survivors-grex/

Quote from: William Schlegel on 2022-10-16, 09:11:33 PMInteresting: I got the S. pimpinillifolium Mexico Midget to test its inclusion on a top 10 list for flavor. First one I tasted was when the weather was still quite cold- a spitter. Later it tasted fine. I don't know about top ten, but a good tomato. So it is very possible that cold grown tomatoes of fine flavor period may just be a difficult row to hoe. I would be very excited to be able to reliably plant my tomatoes a month earlier without protection though!

Just getting tomatoes that would grow well in cool weather and pruduce tasty fruit promptly when warm weather arrives would be a big gain. Especially if the fruit picked at the end of the season in cool weather ripened well indoors.

Steph's thoughts are very interesting.

Frost damage is a bit nonsensical. I bet the center tomato in this image has higher nitrogen content than the tomatoes to its left and right. I thought R18 had some frost tolerance last fall. This one though is the two current tomato crosses I made crossed to each other.

I don't know that I've ever seen much frost tolerance in the fall. Sometimes just the tips of the plants get hit but it's pretty uniform across all of them. Frost tolerance on early volunteers seems pretty common, especially while they are still very small.

Well, I take that back about the fall, just last year I think it was some volunteers that spouted very late, like in September or maybe even it was October all in the apparently same conditions but one shrugged off a heavy frost while the others croaked. Like in you photo they were also quite close together. The one that survived and those that didn't were also much larger than tiny seedlings when it happened. At that time of year though, it wasn't long until a real freeze took that one out too. 

Quote from: William Schlegel on 2022-10-16, 09:11:33 PM.... So it is very possible that cold grown tomatoes of fine flavor period may just be a difficult row to hoe. I would be very excited to be able to reliably plant my tomatoes a month earlier without protection though!

Just noticed this earlier post. I agree good tasting tomatoes in cool weather may be difficult. I base that on the fact that in my garden that ripen in fall after the weather has started to cool do not taste nearly as good as those that mature earlier. It gets hot enough, fast enough here that ripening in cool weather early in the season isn't generally a factor.

In spring I can plant them earlier maybe even find some early season frost tolerance but from what I've seen it might not help all that much. Seems to me that staying alive is about all they might do; real growth doesn't take off until consistent warmer weather arrives.

I think that's an area where genetics and breeding might make a difference, still I wouldn't expect flavorful ripe tomatoes until it got warmer, but if green ones of some size were already nice size on the vines and ready to ripen a harvest might be achieved sooner. 

I think heat is a player in good flavor of lots of things. Strawberries in the hot sun, melons in the hot sun, pretty much any sweet, tasty thing is better if it ripens with heat. Other things like brassica, green beans and so on are just the opposite.

Off the top of my head, it's difficult to think of sweet fruits that prefer cooler temperatures. My earliest berries are honeyberries, which are fairly sweet, but they aren't much earlier than strawberries. It gets pretty warm and sunny before I get any sweet fruit.

I wonder how much of the effect is temperature, and how much is long days of bright sunlight. This could be tested under controlled conditions, such as in a heated greenhouse with good sun exposure but no artificial light.

Can some fruits (including tomatoes) be ripened earlier in warm conditions, despite short days?

Can some be ripened in relatively cool weather if given long days of bright artifical light?

Biological processes happen quicker at higher temperatures. An 18 degree F change in temperature doubles the rate of reaction.

Applying that to tomatoes....

Say it takes 56 days from flower to ripe fruit in my garden.
Then lets say another garden's average temperature is 5 degrees F warmer than mine. That tomato could be expected to ripen 40 days after flowering.

Or in my case, because my average temperatures are lower, if the catalog says that a tomato takes 70 days to maturity, it actually takes 90 days in my garden. That's why when buying commercial seeds, I only buy 55 DTM tomatoes.

The enzymes involved in producing lycopene and various flavor components in tomato ripening are very temperature sensitive.   This is why they tell you never to refrigerate a tomato.
Also some folks have reported that they bought supermarket maters and let them sit in a warm place for several days to improve the flavor.  Because those fruits have been picked at breaker and then refrigerated during shipping and storage.
There seems to be a fair bit of genetic variation in temperature sensitivity, at least there are some varieties that produce tasty fruit in cooler weather.   Ripening time can be longer though, across the board. But still, it is possible to select for tasty cool weather tomatoes.

Various weather outlets suggest a low of 37 to 38 tonight. I expect some minor frost damage in the frost pocket gardens. Unusual for June 19th.

I have the opposite problem, 82F at 6 am and little chance of rain in the next ten days. On the positive side, I have ripe cherry tomatoes and they are so, so good. 

No frost, fog came in. Everything is fine. Still cold for this late in June though.

I had a great frost yesterday. It made it simple to see which lines have a lot of frost resistance, and which have little.

I wasn't surprised that the Profoundly Promiscuous and Totally Tasty Tomatoes project carried a lot of frost tolerance. They descended from Jagodka, the winner of my frost/cold tolerance trials, and from LA1777 which was collected at 11,000 feet in the Andes.

As expected Hummingbird tomato (50% pimpinelifolium) got hit hard.

And Solanum galapagense got magnificently damaged.

A line with a lot of frost tolerance that I didn't expect was  F3 of SunSugar X R18.

One of the most obvious potentially cold tolerant tomatoes I've seen this spring is 50% current tomato from two different accessions. However, because our projects are intertwined, it is also 1/4 Big Hill which means it is 1/8th Jagodka. Last fall it was R18 that was the real standout.

In the direct seeding of orange Promiscuous (The One sub-strain) x Mission Mountain repeated light frosts have done some damage and I really think it might be genetic based on some individuals looking quite sad interspersed with healthy individuals. Frost has never affected the direct seedings this much in the spring before in the 7 years I've been direct seeding.

I haven't seen any frost damage in the Promiscuous x LA2329 and MMM x (Promiscuous x LA2329) direct seeded garden. Maybe the extra fuzz on the seedlings is protective.

When The Greenhouse got hit by frost 2021 twice (my fault, heating failure) only all Paul Robson Plants survived without any damage, i think it was random but who knows, maybe they are a bit cold resistant.