Breeding Potato Varieties From True Potato Seed (TPS)

[Caesar]

Continuing the discussion from Potatoes: What I Have & What I'll Try:

You might say the prior thread was me exploring the general world of Potatoes & similar tubers. On this thread, I’ll be focusing on breeding Solanum tuberosum & closely related plants. So, we start with a recap…

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Planting the store-bought potatoes was a disaster. The red ones turned out scabby… I might have peeled them if they weren’t so tiny at senescence. Clearly it didn’t like the heat. I planted a blue-skinned one the same season, and though unblemished by scab, the insides were blackened with blight. I don’t intend to try that again any time soon.

Regarding the in-vitro & True Potato Seed (TPS) material I got through GRIN from NR6, the story is much more interesting… Firstly, my initial plans never would’ve worked, as I was treating the different potatoes as one and the same when in fact, they were quite different at the cellular level (differing ploidy levels, cytoplasm types and Endosperm Balance Numbers or EBN) – as you can see, potato breeding isn’t always simple, and certain quirks (unreduced gametes, haploid inducers, self-compatibility, sterility, etc.) can complicate it further. Secondly, I killed off the first set of clones with excess moisture, after which I educated myself on the broad strokes of potato cellular compatibility, and ordered a wider arrange of in-vitro clones, seeds & tuber-based accessions. I killed off the second set of clones through premature exposure, with only one tetraploid tuber-based accession surviving to the present (either DTO-2 or DTO-28, I mixed them up). I shelved the project for about a year, until a few months ago, when I started reading really in-depth into potato breeding again. Armed with this knowledge, I ordered a more carefully-researched group of in-vitro clones and seed-based accessions. With my siblings’ help, I also managed to acquire several diploid and tetraploid TPS from Cultivariable, as well as tubers of the diploid Skagit Valley Gold (and for next year, the tetraploid S. acroscopicum Twanoh). The adventure begins!

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The TPS accessions have all been placed into cold storage for the time being, as I want to get TPS from my current live plants before I start germinating new ones. Once this generation’s TPS goes into storage to eliminate the dormancy, the other TPS will come out for planting. I’m trying out several promising wild accessions, disease-resistant tetraploids, and a wide range of diploids, mostly Colombian as they’re the most heat & disease-tolerant types. I’m focusing on resistance to Scab, Blight and Verticillium Wilt.

The tubers are currently growing, with DTO-* in a container, and Skagit Valley Gold now flowering in a raised bed. How exciting! With the right varieties, you really can bloom potatoes in the tropics (trust me, this winter is barely making a dent in the heat). Most diploids are self-incompatible (and incompatible with tetraploids), so I don’t expect seed from Skagit just yet, but the fact that it’s blooming is very promising.

A pic of DTO-*, prior to planting it in a much larger container:

Pics of Skagit Valley Gold:

And as for the in-vitro accessions, for once I have success! I started out with 23 accessions (10 diploids, 13 tetraploids), and so far I’ve only lost 2! Diploid Cuchipa Ismaynin (chosen for pigment & tuber traits) succumbed quickly, while a numbered feral Venezuelan tetraploid lingered in a weakened state from the start, and succumbed yesterday to damping off (it might have bounced back had I not watered from overhead). The rest have remained relatively strong, with every indication that they’ll survive to tuberize, if I keep up the gentle care. I’m currently acclimating them to sun exposure, and they’re getting stronger every day. They used to look pitiful when wilting, now they look like they can take the hot sun and bounce back with little issue. A few more weeks, and I’ll be able to give them a full day of sun.

Here’s some pics of them after planting from the test tubes:

And some more recent pics of some of the more vigorous plantlets:

Among the diploid in-vitro accessions, I chose RN27.01 for pigment and probable heat tolerance, Guincho Negra for pigment, Pirampo for probable heat tolerance, M10 for blight resistance and genetic diversity (wild-based stock), GS 422 for russeting, GS 427 for pigment, BS 291 for diploid self-compatibility, BS 281 for scab resistance, and BS 288 for viral resistance and wild-based diversity.

For the tetraploids, I chose Yuguima for resistance to Tuber Moth & Blight, Canasta for Tuber Moth & Scab, Elmer’s Blue & Bora Valley for pigment (the latter is edible raw, interestingly enough), Sarpo Mira, Unica & Fripapa for Blight resistance and agronomic traits, LT-2, C89.315 & Igorota for heat resistance (all 3 are tropical lines), M17 for Scab resistance, BR03 for Blight resistance, and both for wild-based diversity. The 3 tropical clones should form the base of my tetraploid breeding stock, with the 3 agronomic clones adding blight resistance and other desirable qualities. I can cross Yuguima & Canasta to double up on Tuber Moth resistance while combining Scab & Blight resistance. Likewise, M17 & BR03 to combine Scab & Blight resistance. Elmer’s Blue + Bora Valley would make for a good blue line. The best of each line would go into the core breeding stock.

My plans for the diploids aren’t quite so centralized, as I’ll mainly combine varieties into multiple parallel breeding lines and hope each one bears useful strains. I’ll be doubling up on certain traits to strengthen their genetic basis, and combining complementary traits to cover all weak spots. Anything that succumbs to pest or disease pressure weeds itself out automatically, and the survivors must pass my own criteria to make it into the long-term breeding lines.

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And that’s pretty much it for now. I’ll try to update as circumstances progress. Between the tuber plants, the in-vitro clones and especially the stored TPS, I have a legitimately insane amount of diversity for the founding stock of this project. I was wondering whether to include Haploid Inducers (to get diploids out of tetraploids), but I decided to keep it simple and leave the fancy stuff for later. For now, my challenge will be to get every live plant to tuberize. If I can get tubers out of them, I can plant them out next season and start the second challenge: getting them to flower and set fruit. Once that hurdle is passed, I’ll start the long process of breeding them and saving seed. The diploids will be easy to cross due to self-incompatibility, but the tetraploids will require emasculation & isolation if I want the different lines to cross.

All this work just to tickle my inner mad scientist, and get some potatoes that can handle the tropics. If I get anything good, I hope to send it out to NR6, for other growers to play around with.

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Edit: forgot to add some sources:

GRIN:

https://npgsweb.ars-grin.gov/gringlobal/search.aspx

https://npgsweb.ars-grin.gov/gringlobal/descriptors.aspx?

Cultivariable:

Cultivariable

[RichardRoundTree]

This is amazing and a nice undertaking, i love how much diversity and what you are going for!

[esoteric_agriculture]

Timely post, as I just finished a video on my own experience harvesting TPS grown potatoes. You’d probably enjoy it.

TPS POTATO REVEAL AMAZING DIPLOID YIELD

[Caesar]

@RichardRoundTree

I feel like reading more in-depth definitely helped me focus my project’s goals. At first I was just going for free-for-all Landrace breeding, let 'em cross freely & survival of the fittest & tastiest. A touch of that can still be seen in my chosen method for dealing with the weaker stock & choosing the best stock (if it’s susceptible to anything, let the plague take it, if it’s tasteless or unproductive, cull it). But in taking stock of the different traits each line possesses, and keeping track of who’s breeding with who, I can streamline the process to get desirable results quicker, and combine the best complementary traits together for maximum effect. If I can get all my desired resistances set in the first few generations, I can focus future breeding efforts on taste, productivity and interesting appearance, without having to worry about keeping the stock resistant (unless I add in new lines).

@esoteric_agriculture

I liked & subscribed, great video! It’s amazing to see how much diversity you can get by growing seed instead of clones. And not all are winners, but for a home gardener, most will be good enough, since there’s no industry standards to aspire to (though a rare winner like that would be great too). “Cthulhu’s Jockstrap” gave me a good chuckle, I wonder what trait inspired the Lovecraft reference.

A lot of Tom Wagner genetics in your strains… Fitting, since most of the traded TPS in the states can be tracked back to his projects. It’s a shame that he stopped managing his website. When I first started out, I was eager to get TPS from him, since he seemed to have elite genetics. I’ve since tracked many strains back to GRIN, who’ve already supplied me the TPS.

But as long as I’m here… Would you happen to have any spare TPS to trade? Diploids are where I want to spend most of my efforts, but Tollocan (which I had hoped to get from Tom Wagner) is particularly useful in my blight-susceptible area, as well as any scab-resistant strains.

[esoteric_agriculture]

I have a little seed, which I would be happy to trade. My plan is to save seed from clones which can prove themselves for multiple years, so I’m only doing a massive seedling grow out every 2-3 years. I did save a bit of seed this year, but only just on a whim really. I wish I was able to do hand pollination on Solanum but I’ve been trying for decades now and am giving up on it. I spent a whole day this year doing hand crosses and none of them took, which is what has always happened when I try.
I had gotten seed from Tom Wagner back when he still sold seed. Unfortunately at the time I really didn’t know how to grow TPS seedlings out properly, and, most of his strains just performed terribly here. The most helpful things for me was finding The Rebsie Fairholm Potato breeding book, and then the Oxbow Farm YouTube videos. Between those, I gained enough knowledge to get much better at my process. I’ve been growing from TPS since 2009 or 2010 but this was the first year I did well enough to have potatoes to eat. If you can tolerate Facebook The Kenosha Potato Project has a pretty amazing seed exchange each year.
Also Marianna’s Heirlooms sells TPS from some good breeders. Cultivariable used to be a good source, but they are reorganizing and I don’t think selling much seed lately.
You are definitely right about almost everything in the USA tracing back to Tom Wagner. He is the GodFather of Potato breeding and particularly TPS growing. I know much of his material was sourced from GRIN originally.
I wish I knew who created and named the Cthulhu’s Jockstrap strain. Until this year I had no idea Diploids could be that good in my climate. A lot of progress has been made in the past 10 years in creating Diploids that will be better in a climate that’s not the Pacific Northwest.

[Caesar]

Pm sent.

That multi-year grow-out plan sounds pretty good! It should weed out the lesser varieties that initially seemed promising while giving under-performing seedlings a second chance.

Your troubles in pollinating Solanum concern me a bit… They make it look so easy, but if years of attempts have failed to give you results, I may be in for a challenge.

I have Rebsie’s book! It’s a new acquisition, so I haven’t gotten around to reading it yet, but it looks like it’ll be a helpful resource.

I gave up on Facebook after my high school years, but I’ve been wondering if it’d be worth it to open an account just for plant trading.

Thanks for the reference to Marianna’s Heirlooms, they got some pretty decent-looking varieties there. Bookmarked.

I think diploids get a bad rap because they don’t always perform as well as the tetraploids, but given their better flavors, I think they’re the future of backyard potato growing (and breeding). All that’s needed is to select for increased production and better general performance in the different climates. At the very least, they should be easier to breed without fear of selfing (though if selfing is desired, there’s varieties for that too).

[Caesar]

An update on my in-vitro plantlets:

They were all wiped out by a wilting disease in their containers. No survivors. A few of them managed to tuberize prior to dying back, and one of them has sprouted from a microtuber (variety LT-2). The other microtubers are Unica, Bora Valley, Elmer’s Blue, Sarpo Mira, M17 and one diploid, M10.

Skagit Valley Gold is currently in my raised bed. One viable tuber, so one plant this season. I pray it survives for a few more generations, long enough for me to cross it with M10. We’ll see how it goes.

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@esoteric_agriculture

I got the TPS just last week, thank you! I hope my adventures with TPS will yield better results than the cloned potatoes. At the least, I hope I’ll get something that survives my disease pressure. So far I’ve dealt with late blight, scab, wilt, and early blight… I don’t anticipate things getting any easier.