Frost and Cold Tolerant Tomato Breeding including epigenetic and regular genetic

[Andrew Barney]

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.

[ImGrimmer]

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.

[Nicollas]

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

[William S.]

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

[William S.]

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.

[William S.]

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.

[ImGrimmer]

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.

[Steph S]

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.

[Garrett Schantz]

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.




 

[William S.]

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.

[William S.]

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.

[Garrett Schantz]

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.