Breeding with wild tomato species

[Arjan vD]

He also has "Wild Tomato hybrid (F2) - Lycopersicon arcanum x esculentum".

I bought these as well. This one was bred by Lupinaster himself. I don't really know anything about arcanum but could have something usefull. Only sowed 2 or 3 seeds.

[William Schlegel]

Solanum arcanum is much like Solanum peruvianum and was formerly classified as part of it. From growing it in my garden the last several years I would say it is roughly equal in potential to peruvianum though it hasn't volunteered like peruvianum it has been easy to grow seed to seed.

[William Schlegel]

This one is interesting that it is irrigated with ocean water. Our nursery is a couple hundred meters from the sea and the groundwater and the water in the canals here is very brackish. A tomato that could handle that water would be great. This is one of the reasons I was interested in working with Solanum pennellii because it is supposed to be salt tolerant.

Solanum galapagense and maybe Solanum cheesemaniae also are salt tolerant. I think S. galapagense is closer to the ocean? It is supposed to be a multi-gene trait in the Galapagos Island tomatoes. Which is easy to break because if you make a domestic cross the multiple genes get split up. We have found and commented on a past publication that one solution would be to do gene editing to create novel domestications in these species. We have also speculated in the past that instead of gene editing maybe a high percentage wild hybrid could retain the abilities but still be certifiably organic and open source. Something like a 75% or greater wild species with a large population size. So make a cross, back cross it to the wild until the domestic percentage is small.

I am moving this reply here because for me salt tolerance is a project unto itself and better put into this more general category. The Galapagos tomatoes seem to me to have small pale flowers with inserted stigmas the opposite of Joseph's project. So a high percentage Galapagos variety would probably have small flowers.

[Garrett Schantz]

Comparison between seeds of Peru Currant from HRseeds (Mixed with some Alberto Shatters seeds) and Raindance seeds pimpinillifolium which was collected in Colombia.


Seeds at the top in a bag are from Raindance Seeds, bottom is a mix of Peru Currant originally from HRseeds and Alberto Shatters - saved seed from both last year and intermixed them in a jar.

These are all "true wilds" which are most likely not mixed with any domestic varieties.

I believe that Raindance seeds pimpinillifolium has larger fruit, but smaller seeds than the other two pimpinillifoliums that I have just mentioned here.

No idea about the foliage. Probably a late maturing variety.

[Garrett Schantz]

Went out and pulled S. habrochaites and things earlier.

One of the habrochaites appears to have had much larger roots compared to the others - one of the roots went down pretty deep, the other went sideways and was underneath grass.

https://www.youtube.com/watch?v=qW21XFZ65sA

[Arjan vD]

Decided to buy 2 packs of Joseph Lofthouse peruvianum seeds from EFN. I grew Solanum peruvianum a couple of years ago and since then I get some volunteer seedlings every year so it seems to do well here. This year I am growing 2 strains of Solanum pennellii plus a couple of pennellii crosses I made last year, maybe I could use these to cross to Solanum peruvianum.

[Nicolas]

Taylor (@chance) found a good article about Solanum arcanum LA385 :

High-Altitude Wild Species Solanum arcanum LA385—A Potential Source for Improvement of Plant Growth and Photosynthetic Performance at Suboptimal Temperatures

Here, we investigated the impact of suboptimal temperatures (SOT, 16/14°C), as compared to control temperatures (CT, 22/20°C), on plant growth, photosynthetic capacity, and carbohydrate metabolism. Under these conditions, two genotypes were analyzed: a Solanum lycopersicum cultivar Moneymaker and a high-altitude wild species Solanum arcanum LA385, from flowering onset until a later stage of fruit development. Total dry matter production in cv. Moneymaker was reduced up to 30% at SOT, whereas it was hardly affected in wild accession LA385.

https://www.frontiersin.org/articles/10.3389/fpls.2019.01163/full

Good be a good step toward direct sowing tomatoes in early spring or self sowing tomatoes that can compete early with weeds

[William Schlegel]

Sounds like an interesting accession. We've discussed some other interesting high-altitude accessions in the past but I never requested any of them. I think a few of the accessions Joseph Lofthouse used in some of his work were high altitude. Sort of a limited study with only two accessions. I would like to know how several of the current cold-tolerant domestics stood up in comparison and also some of the other high altitude accessions of several species.

The only two accessions of Arcanum I have grown are two I requested from TGRC because of reported comparative ease of hybridization with domestics as compared to other accessions in the larger peruvianum group. I still haven't managed to make such a hybrid from them, mostly probably just because of lack of time to make very many crosses during the main growing season and also some difficulties with getting controlled crosses to set in the open field. This particular accession might or might not have the same difficulty as most peruvianum group accessions and require embryo rescue to obtain hybrids- which is fine it is just an additional investment in time and equipment if needed.

I was told recently by TGRC that I would need to be with a university or gene bank to request any further accessions the reason being to protect the limited quantities of materials for researchers who rely on them to conduct funded research. I would argue that unfunded or self funded research is also valuable especially as citizen science that could lead to break throughs especially if those break throughs are then made open source. Surely a tomato that could grow well with less heat and likely less CO2 emission would be such a break-through. Though I imagine some university researchers might also be attracted to such a potential.

In regards to having no funding- it definitely does limit how much work a person can do. Honestly I think I have enough accessions of wild material because dealing with any more would be difficult. I feel like already I am not making rapid progress with the ones I have. It would be nice in many ways to just focus on one accession and one project at a time.

[Joseph Lofthouse]

I think a few of the accessions Joseph Lofthouse used in some of his work were high altitude.

LA1777, which was the primary ancestor of my wildling tomatoes came from 10,700 feet elevation.

[William Schlegel]

The other day I smelled my clump of 4 LA2329 Solanum habrochaites and it had that distinctively strong smell the accession is known for. So today I smelled two of the hybrid clumps with promiscuous mothers so essentially 5/8 wild plants. Yep they have that good old LA2329 smell. Pretty exciting! Oddly comforting to have the olfactory confirmation.

The much younger and smaller MMS x LA2329 plants are very odd looking. Very smooth in appearance. Maybe they are something else?! Will find out more as they grow.

Up potted a few wild tomatoes that had gotten a bit bigger. Some cheesemaniae, some peruvianum, another habrochaites accession.

[William Schlegel]

I did a little reading about BER last night, found this really good article which explains it is not all about the calcium but the uptake of calcium in distal tissues of the fruit which can be inadequate if growth rates are too rapid at a certain stage of development.  Apparently it's there from early stages, whether visible or not.  It can be induced by imbalances of other ions including NH4+ and K+.   But they still say that spraying the fruit with calcium actually can solve the problem and prevent BER development.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4246855/

Also this second article which in the abstract comments on the lack of BER in wild tomatoes, has identified a specific IL with BER resistance: IL8-3 carrying BER resistance genes from penelli. 
https://www.sciencedirect.com/science/article/abs/pii/S030442381200057X?via%3Dihub
IDK if that is one of the IL's from TGRC, but would be worth including in the effort to breed paste type tomatoes that don't BER..

I don't know if we can get resources from TGRC anymore at least not without establishing a gene bank or university affiliation. However, we do have some penellii genetics and could make roma crosses.

[Nicolas]

A nice document :

Taxonomy of Wild Tomatoes and Their Relatives (Solanum sect. Lycopersicoides, sect. Juglandifolia, sect. Lycopersicon; Solanaceae)

[William Schlegel]

Solanum chilense finally has two plants blooming. Probably too late though. I tried to hand pollinate this morning then opened the door to let in bees for a few hours. Haven't seen a bombus in awhile though.

[Jeremy Weiss]

Quick question for you who are more knowledgeable about wild tomatoes than I.

Yesterday, due to a frost warning I had to collect all of my remaining tomatoes (and cucumbers), and bring them in to finish up.

This gave me a change to really get a good look at the unidentified cherry tomatoes that showed up on the side patio. At the moment I THINK they are Green Zebra Cherries.

The one thing that gives me pause when it comes to eating them down the road is the fact that, over the years I have planted I don't know HOW many kinds of tomatoes in the pot from which I assume the fruit I got those seeds from came from (I found it dried out on my radiator and thought it was a nightshade berry I had picked out of something, which is how it wound up on the side of the house as opposed to the back with the rest of the tomatoes.) And amongst those WAS a packet of seeds for Lycopersicon glandulosum (I'll keep using the old name for now) which I recall ALSO has green fruit with darker green stripes and, unlike the tomato, ISN'T supposed to be edible (at least in it's pure form).

I looked up pictures of glandulosum, and the fruits in the pictures I see don't SEEM to look like what I have (they're a lot fuzzier). But it would be nice for someone more familiar with the plant to confirm it isn't possible to mistake one for the other.

[William Schlegel]

Does the plant have normal domestic tomato type leaves?

To me the two are quite distinctive:

A domestic cherry with striped, green when ripe fruits is going to have a different pattern of striping, a larger fruit, larger seeds, smoother fruit, and domestic tomato type leaves.

A Lycopersicon glandulosum / Solanum cornelius-muelleri is going to have very oddly lobed leaves, much smaller fruit, much smaller and narrower seeds, often darker colored seeds, and the fruit should have a lot of very short fuzz on it. The fruit might also have anthocyanin patches on the shoulders.

A photo would help, but I had trouble loading a photo on here earlier today.