Breeding with wild tomato species

[Jeremy Weiss]

I love the roadside chicory. My favorite flower. I can't get it to grow in my yard or pasture, seemingly because the better conditions lol.

And then I see everything you guys do to try and get some of the wild ones to grow to try to cross it. Lol maybe treat some like roadside weeds?

I OCCASIONALLY will try and collect from the roadside Chicory plants as well (usually, I'm looking for any plants with white or pink flowers instead of blue, to see if there is any relation between flower color and flavor).

I also have a soft spot for wild/field pansy (Viola arvensis); enough I will collect seed of that and plant it on purpose (I actually saw one last spring that must have had a mutation that made the flowers easily twice the normal size, but, alas I couldn't get any seed out of that one.)

While I am not averse to re-mixing the wild family members back with the domestic ones, I admit I am concerned when one of the major improvements that came with domestication was increased edibility and reduced amounts of whatever toxins it had. Added disease resistance doesn't count for much if the cost is now having something you can no longer safely consume. 

[William Schlegel]

Put out the Big Hill x W? Xl and the Big Hill x W? Best tasting of 2019 in the fenced garden today in rows I rototilled last night between rain storms. Today is the average date of last frost here.

Sort of amazing to me that the elites from Joseph's project have only been in my garden for four years (and his for five). Though there were a few years of the earlier generations before 2020.

[William Schlegel]

https://www.frontiersin.org/articles/10.3389/fpls.2019.01606/full

Was just looking at this article. It's about how introgressions from peruvianum, chilense, habrochaites, and pennellii have helped with the diversity problem in tomato.

Some of the introgressions are quite large according to the article. A common one from Peruvianum is ToMV resistance to tobacco mosaic virus which comprises about 70% of chromosome 9. So when we cross in modern disease resistant varieties we get some decent wild chunks. Perhaps things like the variety Iron Lady F1, that Carol mentioned in her call to action book section on late blight, actually have some decent chunks of wild including peruvianum. Perhaps more than older varieties like the Payette I mentioned. Intriguing if so. If I were starting over with new domestic lines that might be informative. No plans at current though.

Though this would be my scheme if so. I would look for modern hybrid varieties with the largest lists of resistances possible because each of these probably corresponds to an introgression chunk. Then I would pollinate those with about ten+ elites from the promiscuous project. In the promiscuous F2 there would probably be some reproductive difficulties, but then you would probably end up with a promiscuous line with a lot of disease resistances and a lot of corresponding introgressions from all commonly used species.

Joseph in some of his older articles about his first attempts at tomato land races mentioned the genetic value of modern varieties. This article would seem to support that strongly.

I suspect also that this article means that almost any modern variety probably has more introgressions in comparison to heirlooms than we might think. Like all the blue skinned have the blue introgressions. That's a lot of varieties and super common in my garden. So since we haven't been extremely focused on working with older heirlooms only the domestic plants we started with probably already came with some introgressions.

I still think this is a very interesting article! Note: In my opinion it doesn't diminish our work with the likes of Solanum habrochaites in any way. SI tomatoes like S. habrochaites are extraordinarily rich sources of genetic variation. To me this article really calls out how valuable starting breeding with something like Purple Zebra F1 or Galahad F1 is though. Some of these introgressions are huge!

One of the very interesting things I noticed in the last year is that the variety Farthest North https://victoryseeds.com/products/farthest-north-tomato is a cross between Bison and Solanum pimpinellifolium made by Yeager released in 1934! When I was researching some regional tomato breeding history I then found Farthest North was used in the Subarctic tomatoes as an ancestor in Alberta and that they were crossed back in with Payette to create Sandpoint and Kootenai in Idaho- which Tatiana's tomato base says Sandpoint was released in 1978 45 years ago. Payette had been created using what we now consider to be traditional methods with potential introgressions from Solanum peruvianum and Solanum habrochaites. So these introgressions really did start happening quite a while back.

[Justin Jardinier]

To me this article really calls out how valuable starting breeding with something like Purple Zebra F1 or Galahad F1 is though. Some of these introgressions are huge!

What are your thoughts on earliness? I like the idea of Galahad more than Purple Zebra since Galahad is homozygous for PH-2 and PH-3, whereas P. Zebra is heterozygous. But both of them may be rather late season, I think perhaps P. Zebra later than Galahad also.

I luckily received some Galahad F4 which is earlier than F1. And will still be homozygous for PH-2+3 though perhaps might have lost some of the other disease resistance. But I wonder, in general, if we were to follow this idea of making new populations from crossing wild species with highly disease resistant domestics, how we will deal with size and earliness? From what I understand, we rely on the more pure lycs for that.

One exception might be Hot Streak which has a lot of disease resistance (more than Galahad), maybe same as P. Zebra, but larger fruit. But still, not early enough for many of us. And I am still thinking that the size may not be enough since everything shrinks once crossing with wilds, so starting with something bigger than eventually needed seems wise. Plus it's only heterozygous PH-2+3 if I remember correctly.

One thought I had for gaining earliness without having to dilute with early pure lycs, was chmielewskii, which I understand can cause earliness. I haven't been able to find out how easy it is to get that from it though. If that would work, we might still need some oversized tomatoes to balance the size issue?

I wonder maybe even crossing Joseph's tomatoes with highly disease resistant modern hybrids could increase the earliness too. One thing I wonder about is low light conditions though. I'm not clear on how lower light conditions in Northerly cloudy regions effects the earliness 'ratings' the seed companies give, but I am guessing it might be variable, and that at least some said to be early in sunny places, are no good in cold cloudy places. This is one thing arc has me a bit excited about since it was flowering well even when I left some neglected in the corner of my grow room - they were flowering in very low light conditions! I don't know if that actually means anything practical, but I am hoping it might.

[William Schlegel]

Well, what I've done personally is cross them all together.

So I took what was probably Joseph's Brad and crossed it with Brad Gate's Blue Gold and got a short season blue skinned bicolor potato leaf. Then I crossed that with Joseph's Big Hill which is Jagodka x Hillbilly or Hillbilly x Jagodka. Then I crossed that with Purple Zebra F1 and then I crossed that cross with Galahad F1. Now I reckon I might just cross that with something else. Maybe LA2329 or one of the hybrids I have with it like the hybrid with Joseph's promiscuous tomato project. Or maybe also the PH5 pimpinillifolium or one of the crosses with it. So I guess complex crossing rules the day in my tomato garden.

[Cathy A]

What traits did you select for after making those crosses?

[William Schlegel]

What traits did you select for after making those crosses?

Many of the crosses aren't really that far along. In fact with my disease resistance crosses, I don't intend to do much selection at all. I hope to send them to folks like you, who have tomato diseases, for the selections. I'll probably end up with a few favorites though, its hard not to. They wont be disease resistant though unless just by chance alone.

I tend to favor blue skin, stripes, bicolor flesh, and potato leaves.

[Kadence Luneman]

What traits does galapagense have to offer? Please correct me if I got anything wrong.

Not compatible with the promises project because flowers are small and domestic like.

Crosses fine both ways with domestic and pimp.

Carrot leaf.

Introgressed source of antho for domestic varieties we have now.

Possible source of salinity tolerance.

Edible, orange, currant size fruit. (At least from Joseph's improved line via EFN.)

It seems like other than Joseph's improved line there isn't much going on with it? Not being posted about anyway.

[William Schlegel]

Andrew sent me LA1410 Solanum galapagense years ago now and all I've managed is some seed increase. Ive struggled to make crosses with it. It grows best for me in full sun in the open field. It is not a good pollen producer and all crosses attempted failed likely due to the tiny flowers being delicate.   Also tried growing it twice in the ground in the greenhouse- too shady. I plan to plant it in yet another different spot for 2024. So not much to talk about yet.

I added in some seed in 2022 from HR seeds galapagense. I kind of mixed it in. I then noticed two obvious hybrids amongst hundreds of seedlings. HRseeds probably the source but a little uncertain. I made a cross with the cross and then more crosses with that cross so now have 1/8 seeds. The 1/4 strain segregated red and orange in the F1 and the orange one was tasty.

Justin has had better success!

It offers arthropod resistance, salt tolerance, and fun fuzzy little fruits. The salt tolerance is supposed to be multi gene so breaks easily. Maybe could work with enough back crossing.

[Joseph Lofthouse]

To me, the Wild Galapagose tomato, carried by Experimental Farm Network, tastes the best of any wild tomato that I have eaten. (I suspect that it contains beta-carotene, my favorite.)

And the germination rate came in at 82%! I selected heavily to get rid of the hard to deal with germination inhibitors that it had when it arrived at my garden.

It might provide tomatoes with woody stems, that could stand upright, without requiring trellises.

[William Schlegel]

You might end up with a imperfect result, but I think that crossing the Galapagos Island and Galapagos Island descended tomatoes of both species with the promiscuous project makes more sense than many potential crosses. Genetically both groups are divergent from standard domestic. Particularly from a flavor perspective. You can always back cross to get more of the traits you desire in either direction.

Crossing say OSSI tomatoes with about 100 different accessions of red current tomatoes from Peru and Ecuador makes logical sense genetically but flavor and morphological fruit traits would be pretty consistent. You would likely get red cherry tomatoes in the F1. With the orange and yellow Island tomatoes you get a little of that diversity but in a package with better flavor potential. I think we should do both, but the Island tomatoes are the more fun and exciting part of it by far.

[Justin Jardinier]

What traits does galapagense have to offer?

The strong orange colour in the F1 at least is really beautiful! And I love the flavour. The root system seems good, I am hoping it might be resistant to periods of dry weather. And I wonder that it might be rather good for health though I don't know much about antioxidants etc. Also for me it was producing pollen well it seemed, so, not sure if that might be due to different conditions?

Not compatible with the promises project because flowers are small and domestic like.

I don't think I understand that perspective. I mean, tiny brassica flowers attract plenty of pollinators, right? And S. chmielewskii flowers attract plenty of pollinators (and are largely outcrossing), but they are quite small (perhaps smaller even than some larger flowered galapagense accessions?) and yet I seemed to see more pollinators on them than on much larger flowers from the promiscuous project. Due to this I have wondered if flower colour might be more of an issue, or perhaps it is related to pollen production, or both? Plus some galapagense have exserted stigmas, which I suspect might be more important than flower size. And, I saw quite nice flower size on some galapagense accessions. Though I have also seen accessions with smaller flowers and no exsersion, so personally, I am focusing on accessions with larger flowers and a tendency towards exsersion.

I have only been growing the F1 indoors but I am thinking by the looks of things that they might lead to rather short and sturdy plants, which appeals to me. Also I like the smell of galapagense.

To me, the Wild Galapagose tomato, carried by Experimental Farm Network, tastes the best of any wild tomato that I have eaten. (I suspect that it contains beta-carotene, my favorite.)

I notice on their page that the photo of the plant, which has some unripe fruits on it, is not from you. So I was wondering, in your own plants, are the fruits black when unripe? I have only noticed that (not sure actual black or some other very dark colour) with 1 accession and was rather surprised, but they went orange when ripe. I don't know what that's about, whether it's anthocyanin or very concentrated chlorophyl or what.

[Justin Jardinier]

Her's a photo of some exsersion in one gal plant outside, sorry it's not a good photo:


And just for fun, here's an example of some rather extreme exsersion in an indoor peruvianum - not to diminish the galapagense exsersion but just thought some of you might enjoy the picture:

[Kadence Luneman]

Interesting Justin. I thought I read that galapagense had very domestic like flowers. Inserted stigma and closed anther cone.

Hypothetical crosses for Improved Galapagos-
Exserted Orange (exsertion)
Great White (fruit size, color?)
M dw orange hat (early, dwarfing?)

My thought is that I'd see how the F1 looks. Pick one to continue breeding with. Keep it selfed or crossed only within the population, basically keep it 50/50 and see where it goes and what traits pop out. Maybe after seeing F2 I'd pick something to cross back and make 75% galapagense.

[Justin Jardinier]

I thought I read that galapagense had very domestic like flowers. Inserted stigma and closed anther cone.

All but 1 self incompatible species has closed anther cones (at least among the 13 tomato species we deal with - I have not looked into S. lycopersicoides, S. sitiens, S. juglandifolium, and S. ochranthum), that's not a problem at all. And yes, classifying galapagense as having inserted stigma is false, it depends on the accession, as you can see from the photo. It's a self compatible species so yes they have similarities with other self compatible species, but even pre-Columbian South American lycopersicum often have exserted stigmas, according to the papers.

I have no idea how easy it would be to cross an exserted galapagense with an inserted lycopersicum and get exserted offspring, but I've been crossing exserted galapagense with other exserted wild species or wild hybrids and getting exserted offspring easily in the F1 at least. Also, all my F1 gal x lyc or lyc x gal come out pretty much the same (in controlled indoor environment) so, F1 might be hard to judge by - maybe it's like mixing different types of matcha tea powder with icecream, you may as well use sencha powder, it's much cheaper and the subtleties of the difference between expensive matcha and cheap sencha will likely be lost in the mix, overpowered by the icecream! I'm expecting more differences to come out in the F2 though.