I've been dabbling with potato breeding and selection of clones for our own use for the past 6-7 years now. Starting with TPS from Joseph Lofthouse called "Bountiful", then some TPS purchased from Tom Wagner via his New World Seeds and Tubers seed company. The past few years have been truly wonderful since the advent of the Kenosha Potato Project Seed Train, the diversity and abundance of the potato germplasm that arrives via the train really opened up my eyes to how much fun seedling potatoes can be.
Areas of interest to me in the Potato realm include.
Breeding/Selecting high dry matter tetraploid clones capable of produce high yields in my gravelly silt loam soil with out commercial inputs. This year I did not fertilize my tuber-set plot, but I did mulch the plot with a thick layer of green chop after the second hilling. Presumably the decomposition and leaching of nutrients from the mulch provided a certain amount of fertility, while also allowing the potatoes to utilize the complete soil depth right up to the soil/mulch interface.
Breeding/Selecting high carotenoid yellow diploid clone with good yield and good winter dormancy. I've fallen in love with phureja diploids of the Criolla Amarilla/Yema de Huevo type. The texture and flavor and beauty of the deep yellow orange flesh is a fantastic eating experience, but they don't store for crap. I want a diploid that will give me more than a couple of weeds of tasty eating before they shrivel up and sprout all over the place.
Breeding/Selecting a North American domesticated potato species. This one is probably a long shot, but I am fascinated by Solanum jamesii, Solanum cardiophylum, and other EBN1 Mexican/US native potato species and would like to contribute to bringing them into at least partial cultivation/domestication.
That's about it, I've added a picture here from my highest yielding TPS seedling from 2018. The seed was a cross of Sarpo Duro and (probably) Monstruo Azul, (edited to add, this cross was made by Nathan Pierce who gave me the seed)
The image seems a bit big, but I am unsure how to resize it? Advice is welcome.
(https://vgy.me/4fMo8o.jpg)
I resized your image. When linking an image, you can include a width= in the IMG tag. If you edit this post, you'll see what that looks like. You can also directly upload images to this forum and they will resize automatically.
We have some similar projects. I am also working on yellow flesh diploids that tuberize at longer day lengths and have some dormancy and on a North American 1EBN line, which I have been calling by the traditional Mexican name, cimatli. I'm now also very interested in working with P genome wild diploids from South America after discovering this year that Solanum acroscopicum appears to have a lot of potential for breeding.
Love reading about people's potato projects. When things settle here a bit more (busy building up a market garden) potato breeding is something I want to get into.
How do you get the potato seeds to grow? I'm having 0 luck there. The seedlings get their secondary leaves and then just sit there, glaring at me. I actually got one an inch high this year, with four leaves before it died. Wheee. If they don't die early, they die on transplant.
They are really susceptible to damping off. Its good to keep them fairly dry, and to bottom water potato seedlings until you pot them up for the first time. After the first potting up, I find they are pretty bombproof, although there are always one or two that die for no reason.
If you have enough seed, I think it is good to plant really thick and then select for the most vigorous seedlings.
The only other thing I can think of is that it is often recommended to get them out in direct sunlight if at all possible to get some direct UV exposure, due to potatoes being Andean and like quite intense UV like they get back home at high altitude in the equator. Here's a picture of this springs seedlings briefly getting some sun.
(https://vgy.me/dRNrxX.jpg)
I have no trouble with overhead watering but I like to have a good draining, coarse potting soil mix and only sow them when the weather is getting pretty warm. If I sow them too early I have damping off and slow growth.
Overall I have been very happy selecting my own potatoes from seedlings. I have not had any difficulty producing productive and useful ones that work well for us in the kitchen.
I have recently realized a problem with my current batch of varieties I'm growing which is that I have pretty much exclusively selected extremely late maturity potatoes. As of this moment it is the 15th of October and we have yet to have a frost. For a frost pocket in USDA zone 5A, that is about 3 weeks later than normal. And we had about 2 weeks earlier start from the last frost in the spring. So essentially we've had an additional month of a growing season this year. I didn't get my potatoes planted right away in May, they went in in early June. Which means they've been in the ground for 5 months and are still green and growing.
While I think its good to have the bulk of a potato crop be late season potatoes for storage and yield, I ought to have some early and mid season ones to have some potatoes to eat before November!
What I do not know is why this is happening. Are all my potatoes late season because of the way I grow and select my seedlings? Or is it because of the genetics of the TPS material I started with, and if I used different stuff I would get different results.
One concern I've had is that I tend to pot up my seedlings from the starter pot into individual cells in a 50 cell 1020 plug sheet. Pretty much this is the size of cell the seedlings live in till they are planted out. I am wondering if maybe this is too small a cell and it stresses the earlier maturing plants into early tuberization or something and drops the yield? Or was I just unlucky and chose all the really late maturity genetics when I selected my TPS seed to grow?
Regarding the lateness, there are probably two things at work:
Diploids are overwhelmingly short day varieties, so they are holding back until the day length falls under 13-14 hours at the most.
For tetraploids, if you have late blight resistance stock, blight resistance is overwhelmingly associated with lateness.
You will also tend to lose early varieties if you let the seedlings go too long before transplant. If you see tubers forming at transplant with an early variety, it has pretty much formed all the stolons that it is going to and those little plants tend to get lost in the field.
So having 1/3 of my clones descended from Sarpo Mira and about another 1/4 from Tollocan was my problem?
I have started to toss any seedling that already had tubers showing.
The first year I planted indoors under grow lights. Last spring they were planted in the greenhouse, so I don't think light was the problem. As far as soil I use regular garden soil. I guess I'll keep trying until I run out of seeds.
I have just sown some seed purchased from cultivariable, all tetraploid mixs , some popped up within a few days of being in the germination chamber.. will be interesting to see what comes from them.
This has been a break-out year for potato breeding, for me, as I finally found some plants that could produce seeds in my hot summer climate. Blue Belle produced a few berries. And seeds shared by Oxbow Farm labeled "TLSF 12-17 diploid" made a bunch (relatively) of berries. Now I feel like I can really start breeding, particularly for types that will produce seed reliably in hot weather. Here is the best TLSF 12-17 plant.
(https://i.postimg.cc/h4kDXwbB/f-WH-T4bl-RGy1-Hi-DDSe-Ew-MQ.jpg)(https://i.postimg.cc/T3jZYNQC/fullsizeoutput-562.jpg)
I also experimented with some high dormancy and low dormancy diploids this year. The diploid patch got hit hard with a spider mite infestation and I lost a bunch of plants. Some of the high dormancy plants (particularly PI458393) were unscathed and are still going strong, and seem happy that the hottest weather is over. They are blooming profusely, but still not setting any berries.
The low dormancy diploids suffered more from the spider mites, but some are recovering. A couple senesced early. I am going to experiment with replanting these as a winter crop. Our winters are not very cold and I can often have potatoes survive winter undamaged by frost with a southern exposure under an evergreen tree. Low dormancy diploids may be valuable for year round growing in California.
Regarding selecting early plants from TPS. This is something I have been thinking about this year. Early potatoes are very valuable for me, because I can plant them in March and harvest in June, and they don't need a ton of irrigation to get them through summer. (Yukon Gold and Red Norland are great for this.) So, when I found TPS plants that started to form tubers in their pots I just let them finish up, then saved them labeled "early". My plan is to plant them next March all together in an early patch. We'll see what happens. Hopefully they will last long enough in the fridge to still be plantable.
(https://i.postimg.cc/zBYbSBTJ/k-Kkz-Lg-MPTr-Ki-Av-Kkb-Q1-EHw.jpg)
My other thought about this is that, if people are selecting at all for potatoes that make lots of seeds, wouldn't that automatically select for a long season? I think I've heard that early types are much harder to get berries from just because they often senesce too quickly.
Hey Mike! That is great you got some results with that diploid seed. Its neat that it is pink/red flesh too! The parent is yellow flesh without any sign of red that I can see. Possibly crossed to one of the many other diploid seedlings I had going last season. Love it!
So I just took these pictures this morning and posted them on the Kenosha Potato Project fb group, but those posts always get buried eventually. I thought I might put it here more permanently.
It has been having a banner year for potato fertility here, and I've harvested some very large lots of berries from several of the clones I have in my main plot, and even a few of the plants in my seedling plot. One seedling in particular gave me 8 pounds of berries by itself, which is a record for me. So I've got quite a few batches of open pollinated berries in the 2-12 pound range. I wanted to experiment with efficiently extracting the TPS from the berries in large (for me) batches like this.
(https://vgy.me/SaNAYA.jpg)
With folks who do deliberate crosses, it makes sense to individually extract the seeds from a crossed berry to try and get every last seed from the cross to maximize the chances of finding the desired offspring later. But with big batches of open pollinated berries, you can't really give each berry personalized extraction treatment. So I wanted to figure out a way to get the seeds out of the berries with as little pulp and fines following along as possible, and with as little damage to the bulk of the seed as possible, while getting as much seed out as I could in a timely way.
I feel like being creative is overrated compared to stealing a bunch of good ideas from other people and combining them. So I found on Bill's Cultivariable page on TPS growing and saving a mention of the CIP recommending the use of a meat grinder to break up the berries vs a blender, being more gentle on the seed. I have an old meat grinder from a junk store, which has been collecting dust. So I put in the coarsest grinding plate and it very quickly and easily chewed through this tray of berries.
(https://vgy.me/bMpl2l.jpg)
On the Kenosha Potato Project page, Jane Hunter mentioned using an Ikea collander with 2mm holes to separate TPS from berry pulp after blending them. I had a steamer basket with similar sized holes that is designed to fit over a standard stock pot, so the pulped berries were dropped into the steamer basket/collander and a slow stream of water from the faucet was run on the pulp while I stir it around. THIS WORKS FANTASTICALLY WELL! The seeds just start disappearing. Soon you have a pile of green pulp with essentially zero visible seeds. All the seeds fall through into the stock pot.
After repeated pouring off you are left with a batch of fairly clean, very slimy seed in the bottom of your stock pot. When you strain this seed off into a strainer you can easily see how much mucus is bound to the seeds. It takes 5-10 minutes for the seed to partially drain off, and the liquid comes off in a slow ropey continuous strand.
(https://vgy.me/bMKTrA.jpg)
I've switched this year to soaking my TPS in trisodium phosphate, instead of fermenting them to digest the mucus coat and germination inhibitors surrounding the seeds. Mainly because this year I have so many berries to process, and trisodium phosphate takes 20 minutes of soaking time and fermentation takes about a week in my greenhouse at this time of year. I am using a 10% trisodium phosphate solution as detailed in Bill's TPS page on Cultivariable. https://www.cultivariable.com/instructions/potatoes/how-to-grow-true-potato-seeds-tps/
After 20 minutes in the trisodium phosphate the seed strains in a colander like coarse sand. The liquid flows instantly out of the seed vs slowly oozing out for minutes at a time.
(https://vgy.me/S6P3g3.jpg)
After some additional rinsing to remove any remaining trisodium phosphate residue, I dumped out the seed onto a paper plant and put it in my dehydrator to dry, with the heat turned off. Normally I use coffee filters to dry out my TPS seeds but this seemed too big for a coffee filter.
(https://vgy.me/D58A4i.jpg)
(https://vgy.me/Ofl6zk.jpg)
So this protocol seems more or less to work fantastically well for me at this scale, with stuff I already had kicking around other than the trisodium phosphate, which is not sold commercially around here at retail stores, so I had to buy online.
I hope other folks find it useful, and I welcome any suggestions for changes and improvements. One thing that Bill does that I didn't try is cleaning the seed in a bleach solution after the trisodium phosphate soak. I have some bleach, but I just didn't go to the trouble of making up a second solution.
Quote from: Mike Jennings on 2018-10-16, 10:29:24 AM
My other thought about this is that, if people are selecting at all for potatoes that make lots of seeds, wouldn't that automatically select for a long season? I think I've heard that early types are much harder to get berries from just because they often senesce to quickly.
Earlies are typically difficult to get seed from, since it is a race between flowering and tuberization signals. You might have to resort to techniques like tuber pruning or grafting onto a non-tuberous relative to get abundant seed from early varieties.
Yeah, the meat grinder is a nice upgrade over a blender, Tim. As long as the berries are somewhat ripe, you get to dispense with the water processing, which is messy and time consuming.
Bleach will cut back on damping off, which can be transmitted on the seed coat.
So I'm kind of curious about understanding tuber shape and how it is inherited. I've now grown a few wild potatoes, and the tubers are rather like miniature commercial potatoes, small ovoids with fairly smoothish surface features more or less.
Some of the Andean diploid types I've grown behave very very differently, with long branching knobby nested complex structures that are some mixture of a single tuber or a concretion of many tiny ones. And the eyes are often sunk deep into the tuber.
What are the wild ancestors of tuberosum like? Do they have these concreted tubers with deep eyes, or was that selected as an early feature of domestication.
Frankly, while they are interesting to harvest and goggle at when they first come out of the ground, they are not very easy potatoes to use in the kitchen. I'd like any resources on traditional cooking methods for crazy potatoes.
Here's a picture of 4 different diploid clones. Two are Andean seedlings, top left is a very smooth Chaucha Amarilla Larga seedling from this year, top right is BS 283, bottom is BS 286 and the blue crazy tuber in the center is a Criolla Rosada seedling from this year. It is also the highest yielding seedling I've ever grown, with a huge 5 lb yield of tubers. But they are all crazy tubers that I don't know how to use easily. They are basically unpeelable, and challenging even to wash.
(https://vgy.me/VHPKvd.jpg)
If I saved this crazy Criolla Rosada clone, and cross it with nice smooth BS 286, what happens? More crazy tubers? Something in between?
What you most likely have there is a short day adapted diploid that has gone long past its normal maturity under long day conditions. The stolon has thickened into a sort of long tuber and then its normal round tubers formed at the nodes later when the day length dropped enough. If you grew it under short days, you would probably get nothing but rounds. I have taken rounds off of tubers like that before and gotten normal tubers from later planting.
Quote from: Oxbow Farm on 2018-10-23, 08:53:12 AM
(https://vgy.me/VHPKvd.jpg)
If I saved this crazy Criolla Rosada clone, and cross it with nice smooth BS 286, what happens? More crazy tubers? Something in between?
I have no idea, but you should do it!
I have made no inroads to the potato world yet, but i want to. I want to start with diploid varieties first and those that grow well from TPS, and then i can branch out from there. It might be better to start with tetraploids first, but whatever. I really like little yellow fingerling potatoes, but can't seem to find them at the supermarket anymore. I might also like other cool crazy andean colors or traits, so i am open to wide genetic diversity.
I found some diploid TPS the other day, so apparently i still have some seed to play with, but i am always open to others seeds!
I am also interested in wild species. I have a few pea sized tubers of 'M6' Solanum chacoense and i'm interested in S. jamesii.
Remember that diploids are short day tuberizers. That could be a challenge in Colorado.
Quote from: bill on 2018-10-25, 02:32:12 AM
Remember that diploids are short day tuberizers. That could be a challenge in Colorado.
Hmm. That is something worth considering.
Diploids are interesting, especially the extreme yellow flesh types- Papa Amarilla and Yema de Huevo, but for growing lots of useful food, tetraploids cannot be beaten. I grow both, but if I could only grow one or the other I'd drop the diploids in a hot second.
I'd be interested in any resources/papers related to breeding potatoes for starch characteristics. I am very partial to high dry matter/floury potatoes but most of my seedlings seem to be waxy to medium texture. What are the genetics of floury vs waxy flesh?
It is a quantitative trait, so you have to select hard to maintain high dry matter. With so many genes at work, reversion to the mean is a problem. Lots of progeny and relentless selection. You might want to look at getting some chipping type potatoes to cross in, since they are very heavily selected. Some wild species like S. chacoense tend to produce very high dry matter, but also contribute high glycoalkaloids. But, you might look for varieties that have it in the pedigree.
You can see some of the USDA accessions sorted for dry matter percentage at this link:
https://npgsweb.ars-grin.gov/gringlobal/descriptordetail.aspx?id=73171 (https://npgsweb.ars-grin.gov/gringlobal/descriptordetail.aspx?id=73171)
Here's another general question regarding selection, I've been thinking more and more about the complexities of potato selection, even on a homestead scale.
In John Navazio's book "the Organic Seed Grower" I was really fascinated by his discussion in each crop of how to avoid unintentional selection of negative traits. So I've been thinking about the way in which I have been assessing seedlings and wondering what assumptions I've been making that might be leading to rejecting promising seedlings and continuing with seedlings that are not actually what I'm looking for.
The first few years of my TPS seedling growouts, I was always cutting the tiniest microtubers to get a sense of the internal flesh color etc, and I didn't always even do a cooking test of the tuber. I was also preferentially growing out the highest yielding seedlings and rejecting anything below an arbitrary yield cut off.
This year has been kind of a bizarre season for my potatoes, as well as a completely freakish weather season for the most part. The weather was fairly normal in the spring, although the growing season started several weeks early, but in July it started raining and essentially has not stopped. My soils are saturated with water, despite this being a gravel soil that is freakishly well drained. Farms in the area cannot get any corn or soybeans off or really do any tillage or similar work without burying their equipment in the pit of despair.
For my potatoes, I've had an insanely productive year, both for the seedlings and for harvested berries and TPS yield, and the tuber plot. Yields have been massive, but I've also had significant rotting issues, and serious levels of hollow heart in many of my tuber grown potatoes.
It seems from a comment Bill made recently that by selecting to grow the highest yielding seedlings, I was selecting for rapid growth and thus significant risk from hollow heart.
So with yields being variable from year to year based on varying weather, where in the spectrum of seedling yield is the sweet spot of maximum productivity and minimum tuber defects/growth problems etc?
It also seems to me that the tubers from a seedling differ somewhat from the second and following plants grown from tubers. I'm wondering if Doug Strong style "pull starts" would be more like a seedling tuber or a tuber grown plant from that perspective. Even seedlings that seem to give full yield seem prone to producing more tubers in the seedling grow out than the tuber grown plants of the following generation. Or is that my imagination?
Quote from: Oxbow Farm on 2018-11-05, 05:38:04 PM
It seems from a comment Bill made recently that by selecting to grow the highest yielding seedlings, I was selecting for rapid growth and thus significant risk from hollow heart.
So with yields being variable from year to year based on varying weather, where in the spectrum of seedling yield is the sweet spot of maximum productivity and minimum tuber defects/growth problems etc?
It also seems to me that the tubers from a seedling differ somewhat from the second and following plants grown from tubers.
I'm not sure there are easy answers. I actually think the longer I've done this, the more subjective I get with my criteria.
As you say, weather related changes from year to year do make evaluation difficult in years that seem to be an exception to the norm.
I agree with you about tubers from a seedling vs the same plant grown from tubers. Most first year TPS plants last far longer into the season than they will when grown from tubers. That's a difficult thing to evaluate without really grown them out from tubers at least once. Though obviously some are just duds. In 2017 I grew out every 2016 TPS seedling that produced tubers, just to be able to get numbers on evaluating the "what if's" of which ones and what kind of percentages should be saved or culled.
Quote
I'm wondering if Doug Strong style "pull starts" would be more like a seedling tuber or a tuber grown plant from that perspective. Even seedlings that seem to give full yield seem prone to producing more tubers in the seedling grow out than the tuber grown plants of the following generation. Or is that my imagination?
Pull Starts to me seem like tubers grown from clones, but with them skipping the pretuberization phase of growth. Pull Start growing seems to start the process of senescence, and most Pull Starts begin to tuberize immediately. (I've actually wondering whether doing it with sizeable amounts of short day diploids might trigger earlier tuberization in short season climates.) I think there is something going on with Pull Start plants hormonally (or something else biologically?), that is deficient in something tuber grown plants have.
The quantity of tubers is limited to quantity per stem, so plants with many stems produce smaller tubers, but more of them. Simon Smart has done some research about this in his Phd dissertation, but essentially concludes that stem spacing is largely what most impacts yield and tuber size. There is an ideal for yield based upon this, but that probably is different with different varieties. I will tag you in a threat on KPP.
https://www.facebook.com/groups/KenoshaPotatoProject/permalink/10154553083022859/ (https://www.facebook.com/groups/KenoshaPotatoProject/permalink/10154553083022859/)
Here is the link if you want to download the pdf of his dissertation.
https://www.dropbox.com/s/dbgvmjt4d61ld4o/Improving%20Uniformity%20of%20Potato%20Crops%20-%20final%20version.pdf?fbclid=IwAR2tlG0258fjvxQMriDGs3G1Qsgavixbhvj1OKml7UOIp9ngxqvPyXEyLOE (https://www.dropbox.com/s/dbgvmjt4d61ld4o/Improving%20Uniformity%20of%20Potato%20Crops%20-%20final%20version.pdf?fbclid=IwAR2tlG0258fjvxQMriDGs3G1Qsgavixbhvj1OKml7UOIp9ngxqvPyXEyLOE)
WendyM summarizes it like this
QuoteRather than size of the potato seed tuber is the weight that correlates with higher yield.
Early emergence correlated to increased canopy ground cover. About 2-3 weeks after emergence the tuber initiation starts. The total amount of tubers is fixed early in the plant development.
For those doing pull sprouts there was a mention that removing the seed tuber after stem development decreased yield.
Multiple thin stems equal smaller tubers and fewer thicker stems equals larger tubers and stem size/weight is the important element.
When the diameter of the stem below ground and the weight of the stem above ground is large then the result is better.
There are few things that I knew from before...
Seed stored at 2C slows physiological aging. Warmed tubers had faster emergence. Physiological age of the tuber has effect on the apical dominance (old seed results in multiple stems/smaller tubers)
Next time I grow potatoes I would select cold stored but chitted tubers for early apical emergence/large canopy ground cover. Weight seed tubers of 2.0-2.5onz and plant them at 12-16in spacing.
If they result in 3-4 thick heavy stems per plant cluster then I should get the most uniform tubers+bigger yield.
I guess I'll use a recently harvested seedling to kind of discuss my confusion on how to proceed with certain seedlings and how much of a struggle it is to figure out if you should keep a variety or not.
This potato is a seedling from a batch of bulk seed collected from my 2017 seedling row of Sarpo Mira X Bulk mix that was crossed by nathanp and he gifted to the KPP seed train. This plant produced 1 pound 12 ounces of these coal purple round tubers.
(https://vgy.me/7DXuzR.jpg)
My previous cut off was 2 pounds. I would toss any seedling that yielded below that.
When I cooked a tuber of this variety I have generally been steaming them in chunks or whole depending on the size of the tuber. This tuber did this after 10 minutes of steam.
(https://vgy.me/OqFbtS.jpg)
(https://vgy.me/jUAbPM.jpg)
I don't exactly understand what is going on with the skin, but it has about the flour-iest, highest dry matter texture of any potato I've ever had. It also has some light purple streaks in the flesh before it is cooked, so the cooked tuber flesh is a bit grey.
There are a lot of aspects to this potato that I don't like. I don't like black/purple russets that are shaped just like rocks. They are impossible to see when you are harvesting. I don't like purple tinted/streaked flesh. It looks grey after it is cooked. The skin seems oddly thick but doesn't hold together when cooked in steam. The yield was low.
But I LOVE floury potatoes. Shouldn't I keep this one because it is unusual and so floury? I don't know that I would want a huge row of these, but if it is fertile then wouldn't it be possible to breed a better skin color, yield size, crossed to it to make a good potato?
QuoteShouldn't I keep this one because it is unusual and so floury
Yes, if that has the floury genetics you are looking for. Plant that one next to another one that has those traits, or alternate several in the same row, or in adjacent rows to try to get open pollinated crosses. You can always work on the yield, or select for yield as a secondary trait once you have TPS from something like this.
I'd keep it for a while to breed with it.
Fast cooking and fluffy, it looks like an excellent dumpling potato. No peeling of hot potatoes is great, just scraping out with a spoon makes life easier. You probably know this, mentioning it just in case, but poke a hole in them when steaming, they explode sometimes if you don't. A very messy experience when you are lifting the pot lock just at that time... I got covered in potato mash last week because I forgot.
It does really look like a rock though. It's funny, you got rocks and get rock coloured ones, I got sand and get sand coloured ones. Must be Murphy's potato breeding law.
If you have some sibling tubers of that cross, which meet your criteria in colour and yield and show signs of good starch, I'd try crossing it with them. The genes are in there and good starchy varieties for crossing are hard to find, at least in Europe. Most of them are not the best producers, lousy berry keepers or don't have much pollen. I keep two varieties, Mandel and Mehlige Mühlviertler, because of excellent taste. But other than taste and starch they are not exactly great varieties.
Regarding earliness on tetraploids :)
I get a good amount of earlies when selfing or crossing mid season varieties. Not a lot, but good enough. It's my lazy way to find bonus earlies from other projects.
Selfed late season plants or crosses between them seem to give late season seedlings most of the time. Maybe one in 10 could pass as mid season, but no earlies so far.
I have not done a late x early cross, but plan to do some next year. Probably things will be all over the place in the offspring, with a tendency towards lateness, but I'll try anyways.
Earlies are a pain to breed with in my experience. Selecting for good berry producers might cull them as a side effect. Some years my earlies don't even bother with flowering at all. But they do flower nicely when they are in the right mood. Cool temperatures are helpful. I got 1 berry this year, had about 30 plants with lots of flowers and plenty of good pollen varieties around them. The single berry wasn't fully developed when the plants finished, it had ~10 seeds of dubious quality. Yay.
The slightly easier way to breed with earlies is to use their pollen (if they have fertile pollen) and to match up flowering time with a mid season variety. This usually gives me more berries, more viable seeds per berry and a good percentage of early seedlings.
From my experience young rootbound TPS seedlings give a lower yield than they could if they had been potted up or transplanted in time. Especially the earlies suffer a lot from that, since they start tuberizing early. I try to avoid rootbound seedlings, but sometimes spring is late and there isn't much to do about it. Those years I typically get something like three biggish tubers from early plants. I give them a second year chance then, if they are keepers in other criteria. Having a high cut off weight for the seedlings would cull those without revealing if they are true low producers or got stopped from being rootbound. I think your cut off weight is good for the late varieties, they usually don't improve weight much in second year for me. But I'd not apply 2 pounds to the earlies, 1 pound on early seedling plants isn't too terrible performance, at least in my growing conditions.
So it seems like I can never find a seedling that is 100% what I am looking for.
This seedling yielded just about the maximum possible yield a potato is capable of, at 13 lbs of tubers. I wonder if I'll ever see single plant yields like this ever again, this year was such a bizarre weather year with almost an extra month and a half of growing season when you add the early start and super late end. Plus colossal rain from July till winter.
(https://vgy.me/YzV6b6.jpg)
They did have a bit of hollow heart, and many of the tubers were on the small side.
(https://vgy.me/PSiZ1r.jpg)
I cooked them up and they were extremely floury, the flesh texture was just exactly what I love. I had steamed the split half tubers in the picture till they were fork tender, and the skin peeled away from the flesh, so I had tried the flesh separately. When I tasted the skin it was EXTREMELY BITTER. The bitterness lingered in the back of my mouth and throat for several minutes after eating the skin from one of the half tubers. Several hours later and my stomach does not feel any discomfort, but the initial bitterness was so intense that I am pretty sure that this potato has unsafe levels of glycoalkaloids.
In the Cultivariable podcast with Tom Wagner, https://www.cultivariable.com/tom-wagner-of-tater-mater-seeds/ (https://www.cultivariable.com/tom-wagner-of-tater-mater-seeds/) Tom talked about liking to use Lenape (B5141-6) as a parent variety, even though it had been found to have excessive glyco levels. So I'm wondering about the wisdom of saving this one as a parent for high yield and flouriness, despite the bitterness. I don't have any idea how one goes about testing for glycoalkaloid levels other than tasting the spuds. I've never had a seedling that I found offputtingly bitter before this.
Adults can usually handle quite a bit of glycoalkaloid without getting sick, but if you can taste bitterness, the level is outside the safe zone. If it rises to burning/tingling, then you are probably above 100mg/100g, which starts to get dangerous. There's no reason you can't keep breeding with it though - most of the progeny will probably have much lower levels, even if they are just self progeny.
I have not bred with bitter ones, so I don't know.
The few bitter TPS plants that I had so far were undesirable in more traits and they just became compost right away.
I'm just a flyweight of kids size, but did not feel sick after taste testing them either. Just had one bite though, it's such a nasty surprise.
I would like to derail this topic a bit and insert some of my reflections on potato breeding. I would be interested in hearing thoughts from others on these ideas. If this is best left as a new topic, I can repost this separately from this one.
When I first set out to work with potatoes several years ago, I had been heavily influenced with the desire to build a potato landrace, in the more modern sense, meaning heavily diverse, abundantly fruitful, and adapted to my local climate. Ideally, that would have been productive TPS seedlings that resulted in production in the seedling year. I have come to realize that most of these goals are largely not possible without heavy selection (but of what?), and not just relying on the selection of what produces fruit(berries) in my climate. The landrace philosophy is greatly attractive to me, and constant, recurring selection towards what grows well for me, in my area, makes a great deal of logical sense. I have move towards doing that largely with all other crops I grow. That includes tomatoes (though I do still track pedigree and F# with dehybridized plants and lines), beans, squashes of all types, greens of all types, etc. Just not potatoes.
What I have found in relying chiefly on selection by berry production is that the results skew heavily towards potatoes that produce berries, but often lack yields I am happy with. Largely, this is anecdotal and reflects my thinking as I do not have hard evidence and numbers on this, yet it seems more true the longer I work at this. Likewise, relying on production of tubers from TPS seedlings provides subpar yields that at best in the seedling year, would be difficult to rely on if food production was necessary.
I have corresponded with others who have also made attempts to save TPS seed from a large diverse crop of potatoes, only to be disappointed with the results of a high percentage of the TPS seedlings. I suspect this is evidence that selection of parents is the most important factor in potato breeding. I strongly suspect that there is a regression to the mean with selection for berry or TPS production both for volume from varieties, or of volume saved from many varieties accumulated, that brings average yields down if I am not carefully selecting for parentage and making intentional crosses, rather than just relying on open pollination. This practice seems to prove counterproductive to the end goal of producing valuable and useful TPS plants to be regrown in future years.
Being more careful to make crosses, and forcing hybridization seems to produce much higher yields in the offspring. Using varieties that produce high volumes of berries that are often selfed, rarely produce offspring that are high yielding for tubers. In fact, these varieties often seem to only produce middling results as parent unless I am using their pollen to pollenate other varieties.
I can modify my goals or plans to be far more selective with which potatoes I allow to be parents of TPS I grow out. But this seems to be in some contradiction of principle with the theory that abundantly fruitful potato plants should eventually lead to producing high yields. I will point out that I do think these goals are not easily aligned, and possibly cannot be aligned.
There is a case to be made for wanting potatoes that are all of hybrid offspring (and yes I know in theory even selfed potatoes are hybrids of a sort, but all are not equal). This makes a good deal of sense, assuming it is a case of hybrid vigor. A minority of selfed plants might also produce equally, but the percentage of good yielding seedings from selfed TPS is much lower. Plants that produce a high percentage of selfed berries tend to produce low percentages of good yielding potatoes, and low percentages of seed that is open pollinated.
What I am moving towards is using only specific, proven varieties to pollinate other varieties. The longer I have been growing out TPS, the more I find I am selecting not for production in their seedling year predominantly, but production when grown from tubers in their 2nd year. It is becoming increasingly important to me to identify which varieties are of highest value in using as parents in crosses, and less about just wanting a larger diversity of plants that are open pollinated or selfed, or produce high volumes of berries or TPS. I do want both, but intentional focus on parentage seems to be of higher value in breeding, than just broadly growing out TPS from a diverse mixture. Paying attention to varieties and record keeping with notes is becoming more valuable with potatoes than with any other crops I have set my hand to grow. A modern landrace of potato plants then, really, is built from varieties that have proven themselves primarily by yield and success in a local climate, and proven success as parents. That is not easily done without some semblance of tracking the productivity of offpsring out of each potato clone by, and a track record that cross references multiple years and multiple generations of plants for evaluation.
Some of this should be a bit obvious upon reflection, but it is not the direction I thought I was headed in when I began this journey with TPS.
Selection then, might be most usefully done with regard for proven parentage of useful tubers of acceptable yield (or other desired traits), with those potato varieties becoming central to a breeding program.
Introduction of new potato varieties (clones) is done not only for the purpose of having a wide genetic base, and/or hoping for mass open pollination with other varieties. It is instead done with the goal of identifying which varieties will be most useful as parents to use in future cross pollinations.
My landrace, therefore, has become a genetic pool of plants that I have deemed to be useful, productive parents. Not really a landrace at all with how modern landrace breeders normally define the term. This is very different from what I seen with other crops I have grown.
My experiences are similar to yours, Nathan. Making modern landraces out of clonally propagated polyploids is a tall order. Odds of success would go up in diploids, since they will hold onto recessives longer. Self-incompatibility will help as well in maintaining the population over generations. But it is always going to be easier to propagate rare and superior genotypes clonally than to try to fix them for sexual reproduction.
I haven't found much conflict between yield and berry set in late varieties, but in early varieties, they are just about inversely proportional.
Even though I love the idea of modern landrace breeding I don't apply it to potatoes. The main reason is that our European pollinators are not interested into potato flowers at all. On a row of a male sterile variety, grown between fertile varieties, I might find a single berry on 20 plants. Which in turn means that basicly all volunteer berries on high fertile varieties are selfed. After just a few generations things would run into inbreeding depressions by default.
The other reason is that the interest in starting from seeds (anything really, even tomatoes) is basicly nonexistant in my neck of the woods. People don't want to start seeds indoors and care for seedling plants for 6 weeks. Which has to be done for tps in our climate or you won't harvest more than micro tubers.
In my breeding I'm just looking for good tubers to propagate and eventually share them with interested gardeners. Being in Europe I can't really sell or even give away 'unrecognized varieties' for food anyways. However I can share food crops for experimental, educational or ornamental purpose lol yeah, the idiocy of modern day regulations. Potatoes used to be a huge part of our foodculture, but they are disappearing from our plates. All food has to be a certified variety, but those all look and taste the same and almost all are 'all purpose' i.e. usable for most things, but not really good for anything. It's not surprising that people stopped eating or growing those incrediby boring round clumps of uniform and tasteless things advertised as potatoes.
My simple motivation in breeding potatoes is to bring back some diversity and flavour, at least into home gardens. It's the last place in Europe where food diversity can thrive until laws are changed.
But I'm rambling and drifting away from topic here, sorry.
However that's why most of my crosses are deliberate crosspollinations. I'm trying to match varieties that compliment each other in disease resistance (scab mostly), food quality and unique colour or shape. For me good berry setting ability and selfing ability mainly plays the practical role in regards of 'it needs to be fertile to breed with it' and when it selfs there are no sterility issues in the next generation.
Since I can't produce more than we eat at home, I have to plan carefully what cross is promising enough to make and grow.
I just sow a few seeds from selfed volunteer berries. If I sow them it's just to get an idea of the traits hidden in a certain variety. The offspring can produce decent or not. I guess the underlying issue here is inbreeding depression. Older heirloom varieties, which were probably selfing for some generations already, are not going to have much high yielding offspring when selfed, but might be great for crossbreeding because of other traits and hybrid vigour kicking in. When growing selfed TPS from modern varieties with documented pedigree of a varied parentage, the harvest is usually quite good. I avoid going into a selfed second generation, just occasionally grow them when I know more about their parentage and can guess that inbreeding depression won't set in already.
However I'm interested in finding out how fast inbreeding actually affects potatoes and will probably inbreed a line on purpose. This year I grew a selfed F1 from a variety called Heiderot, which has 4 different grandparent varieties. The F1 had good yields on average (when I exclude the ones being too late for my short season). I plan to grow a F2 next year and don't expect yields to drop just yet. But I have a feeling that inbreeding depression will show up within roughly 5 generations already. Will see.
I have never been particularly interested in landrace plant breeding for most crops. I also do not think that potatoes are particularly well suited to landrace techniques, at least under my conditions. It seems like the only way to do that effectively is to use diploids, given their combination of pollen fertility with self incompatibility. With pollen fertile tetraploids, I find that plants that produce huge crops of berries are almost certainly self pollinating to a huge extent. I do think I have relatively high levels of crossing in my potato plantings, since I see the bees working the flowers actively, and I know most of the stuff I grow is pollen fertile.
This year I collected approximately 13 ounces of bulk TPS from my potatoes. Over 50% of that was from one variety that produced 7.5 ounces of seed (that I managed to harvest). I was very happy to collect so much seed, and I happily was able to sell some wholesale and donate a large amount to the Kenosha potato project.
For my own TPS grow-outs though, I am more interested in the tiny batches of seed I collected from other potatoes with much more sparse fruiting. It seems much more likely to me that these indicate successfull crosses, and are likely to produce a variety of offspring to select from.
I remember a few years ago on HG Joseph was advocating breeding for an "abundantly fruitfull" potato landrace, which would produce high yields of tubers and large amounts of seed. It isn't clear to me that that is a feasible goal, at least under North American conditions. I do think it is important to focus on male fertile lines as much as possible.
For my own projects, I don't know if I will begin doing careful planned crosses though. It is very difficult for me to commit that kind of time to hand pollinating at that time of year. In general hand pollinating is not a breeding technique I'm particularly interested in, simply due to lack of time.
What IS fairly easy for me to do is grow out large numbers of seedlings, and to evaluate them over a number of years. I've been really grateful to have access to Nathan's extra TPS crosses, as they have been very fun to grow out.
One area I would like to explore more is to better understand the difference in behavior of TPS seedlings from the seedling year to the first and second tuber years. I would like to get much better at evaluating seedlings for their potential. I have found that the results from the seedling year don't necessarily translate to the tuber grown years, and I want to understand better what changes can be predicted. If that makes sense.
I think what I'v settled into with my sweet potatoes is saving superior plants as clones and growing them along with new sprouts and new varieties each year. My storage capacity is limited so I'm going to have to set a limit of around ten or so to keep for cloning and replace as better ones show up. Extra seeds go into the archived grex.
I know they are very different things but might something like that work with potatoes as well?
Tim: Wonderful on producing so much TPS!
When I was originally advocating for "abundantly fruiting" potatoes, that might have meant 20 berries per plant. Wow, we have advanced a long way in a decade!!! I'm reading reports recently about hundreds of berries per plant. I think that today I would advocate for growing varieties which are "reliably fruiting".
My polyploid plant breeding projects are primarily dealing with varieties that are cloned. So once a suitable clone is identified, then it is cloned year after year. Predicting outcomes of manual crosses is much more difficult with the polyploids.
My experience with potatoes, is that 2nd year tubers tend to do worse than the first year plants, and a few do much better.
I thought that potatoes were strongly outcrossing; is this not the case?
From the Cultivariable site:
QuoteThe potato of commerce is tetraploid, bearing four copies of each chromosome, resulting in a sort of built-in hybrid vigor that typically allows them to grow larger and yield more than diploids. Potatoes are outbreeders and experience inbreeding depression. As a result, they do not grow true from seed. Every potato plant grown from TPS is genetically different.
How do they become selfed and inbred if they are outbreeding?
My interest in TPS is different now from a few years ago. A few years ago, I was very interested in breeding a "tower potato." I now think this may be impossible, and besides, I'm not sure if it is desirable.
I'm now more interested in the fact that the native climate of some potato species and varieties is rather like the high desert climate of Colorado, and that potatoes can be dry farmed. I'm also attracted by the ability to avoid purchase of certified seed and the trouble of overwintering large amounts of seed potatoes; planting an expensive seed potato in a marginal dry-field where yield will be low doesn't seem like the brightest idea.
I'd like to grow TPS in a garden plot to form micro-tubers, which could be tasted to eliminate bitter ones, before planting out on a dry field for production the next year.
If I only harvested TPS from clones in their second (or third) year after evaluating yield, would I avoid the problems discussed above?
Quote from: Gilbert Fritz on 2018-12-04, 04:03:33 PM
How do they become selfed and inbred if they are outbreeding?
Diploid potatoes have a strong self incompatibility mechanism, but it is not functional in tetraploids for some reason involving the doubled genome. So it is easy for a pollen fertile tetraploid to produce a lot of self pollinated seeds since the pollen is released in immediate proximity to the stigma in Solanum flowers.
Quote from: Joseph Lofthouse
Tim: Wonderful on producing so much TPS! I think that today I would advocate for growing varieties which are "reliably fruiting".
I think that this is an apt way to put it, and a very realistic goal. I am certainly content with ones that behave like this. Tim certainly has had a few that are abundantly fruitful. I've had one or two, but have found that they mostly produced high volumes of selfed TPS.
Quote from: Oxbow FarmFor my own TPS grow-outs though, I am more interested in the tiny batches of seed I collected from other potatoes with much more sparse fruiting. It seems much more likely to me that these indicate successful crosses, and are likely to produce a variety of offspring to select from.
This is what I aim to do when I an unable to make specific crosses take. It's a much better likelihood of being crossed, resulting in seedlings with highbred vigor instead of selfed. This year, for example, I did not have any successful hand pollinations.
Quote from: Gilbert FritzI'm now more interested in the fact that the native climate of some potato species and varieties is rather like the high desert climate of Colorado, and that potatoes can be dry farmed.
If by dry farming, you mean no irrigation, then I dry farm everything I grow. I only water at time of transplanting seedlings. That will limit yields with many crops, however, including potatoes. Potatoes mostly like regular watering.
QuoteI'm also attracted by the ability to avoid purchase of certified seed and the trouble of overwintering large amounts of seed potatoes; planting an expensive seed potato in a marginal dry-field where yield will be low doesn't seem like the brightest idea.
I'd like to grow TPS in a garden plot to form micro-tubers, which could be tasted to eliminate bitter ones, before planting out on a dry field for production the next year.
This is fairly realistic, but it's still a bit of guesswork to determine which ones to save for seed tubers and which ones to drop. As for bitter tubers, unless you are working with wild species, you won't run across many. I think based on what I've grown the past few years, the percentage of truly bitter and inedible ones must be in the ballpark of 1 out of every 500 or so.
QuoteIf I only harvested TPS from clones in their second (or third) year after evaluating yield, would I avoid the problems discussed above?
Somewhat yes and somewhat no. The no first. There are too many genes involved with tetraploids and if you want to stabilize a trait by inbreeding (like tomatoes), you probably would need something over 20 generations for clones that have rather uniform genetics. Widely divergent segregating potatoes could take many more generations. But you would hit inbreeding suppression long before then. Researchers currently are trying to stabilize highly inbred diploid populations, which can be stabilized more similarly to tomatoes in 7-8 generations (both diploids). The trick for them is to find ones that do not suffer inbreeding suppression, if possible.
I think the value of selecting TPS from clones that are proven for several years in your climate is that they are proven in your climate, especially if they produce berries. I have zero interest in potatoes if they do not produce berries. The could be the world's best yielding potato, but that does nothing for me if they cannot be a parent. If I have two consecutive years with no berries, that is one I will drop. TPS from those that are proven in your climate are probably more likely to produce desirable TPS plants, rather than ones that struggle in your climate and growing conditions. That is exactly what I would advocate, that one of the best things you can do is select tubers to be good parents to breed with. And then, one way or another, using crossed TPS from them, rather than selfed TPS.
The self incompatibility mechanism in diploids is missing in some commercial diploids. I grew Mayan Gold and Inca Bella, they both set fruit when selfed.
Which makes me wonder, if they are easily making selfed fruit, how many more diploids do? Is the mechanism really present in most diploids or is it just some? Which ones?
I have one diploid that is self compatible, but I haven't grown seeds form it yet to see if it shows much inbreeding depression. I will be saving seeds of it this season.
QuoteIf by dry farming, you mean no irrigation, then I dry farm everything I grow. I only water at time of transplanting seedlings. That will limit yields with many crops, however, including potatoes. Potatoes mostly like regular watering.
And I'm in a much more arid location. But, this guy is growing dry-farmed (no irrigation) potatoes and other vegetables on 12 inches of rain. On the other hand, he has a somewhat cooler climate than I do. http://bobquinnorganicfarmer.com/dry-land-vegetables/ (http://bobquinnorganicfarmer.com/dry-land-vegetables/)
I'd guess that a targeted breeding program would end up with potatoes that ran roots much further from the center of the plant to capitalize on the wide spacing of dryland farmed plants.
Gilbert, you might consider trying some Cimatli potatoes from Cultivariable. They might be more adapted to such a dryland system than tuberosum.
https://www.cultivariable.com/product/potato/potato-wild-relatives/cimatli-5-tubers/
Quote from: Doro on 2018-12-05, 01:47:20 AM
The self incompatibility mechanism in diploids is missing in some commercial diploids. I grew Mayan Gold and Inca Bella, they both set fruit when selfed.
Which makes me wonder, if they are easily making selfed fruit, how many more diploids do? Is the mechanism really present in most diploids or is it just some? Which ones?
I am curious, are you sure that they are selfed and not open pollinated? If there are other potatoes (diploids or tetraploids), it is possible there was cross made unless there is a significant isolation distance or complete lack of overlap in flower timing.
There are quite a few self compatible diploids, but not much is documented, other than those with the Sli gene. The Sli gene is being used in commercial breeding to develop highly inbred diploid varieties, in particular varieties that do not suffer as much inbreeding suppression. I've grown a few with the Sli gene and made crosses using varieties with it. But I have also found other diploids that I suspect may be self compatible just based on large numbers of berries compared to neighboring plants. Either the Sli gene is more common that generally supposed, or there could be other genes in play doing the same thing.
Quote from: Gilbert Fritz on 2018-12-05, 08:46:49 AM
I'd guess that a targeted breeding program would end up with potatoes that ran roots much further from the center of the plant to capitalize on the wide spacing of dryland farmed plants.
I find this is actually counterproductive unless it is a variety that spreads widely. Gaps between rows of potatoes tends to actually dry the soil out. Having full foliage cover conserves water similarly to mulching. The best yielding potatoes, in my experience, tend to be the ones that quickly provide full foliage cover of the soil first.
Nathan, I am pretty sure they are. After reading about them being self compatible in a potato database I got curious and put a bag over some flower clusters to keep pollinators out. They were still setting fruit readily. Despite being a bad berry year. It was very interesting to watch them keep most of their fruit while other varieties aborted a lot of berries because of heat and dry conditions. I'd say they are very fertile.
This white paper has some information that looks particularly useful with selection of TPS seedings for earliness/lateness in their seedling year. I plan to pay attention to this next year.
https://link.springer.com/article/10.1007%2FBF02365785?fbclid=IwAR2Kry5nAiKZmGnFvpnjr_vsCaPdwBmegXR4ih_O9p1GJXKzOCO6f8d-wRA (https://link.springer.com/article/10.1007%2FBF02365785?fbclid=IwAR2Kry5nAiKZmGnFvpnjr_vsCaPdwBmegXR4ih_O9p1GJXKzOCO6f8d-wRA)
Quote from: nathanp on 2018-11-28, 05:37:01 PM
I would like to derail this topic a bit and insert some of my reflections on potato breeding. I would be interested in hearing thoughts from others on these ideas. If this is best left as a new topic, I can repost this separately from this one.
When I first set out to work with potatoes several years ago, I had been heavily influenced with the desire to build a potato landrace, in the more modern sense, meaning heavily diverse, abundantly fruitful, and adapted to my local climate. Ideally, that would have been productive TPS seedlings that resulted in production in the seedling year. I have come to realize that most of these goals are largely not possible without heavy selection (but of what?), and not just relying on the selection of what produces fruit(berries) in my climate. The landrace philosophy is greatly attractive to me, and constant, recurring selection towards what grows well for me, in my area, makes a great deal of logical sense. I have move towards doing that largely with all other crops I grow. That includes tomatoes (though I do still track pedigree and F# with dehybridized plants and lines), beans, squashes of all types, greens of all types, etc. Just not potatoes.
What I have found in relying chiefly on selection by berry production is that the results skew heavily towards potatoes that produce berries, but often lack yields I am happy with. Largely, this is anecdotal and reflects my thinking as I do not have hard evidence and numbers on this, yet it seems more true the longer I work at this. Likewise, relying on production of tubers from TPS seedlings provides subpar yields that at best in the seedling year, would be difficult to rely on if food production was necessary.
I have corresponded with others who have also made attempts to save TPS seed from a large diverse crop of potatoes, only to be disappointed with the results of a high percentage of the TPS seedlings. I suspect this is evidence that selection of parents is the most important factor in potato breeding. I strongly suspect that there is a regression to the mean with selection for berry or TPS production both for volume from varieties, or of volume saved from many varieties accumulated, that brings average yields down if I am not carefully selecting for parentage and making intentional crosses, rather than just relying on open pollination. This practice seems to prove counterproductive to the end goal of producing valuable and useful TPS plants to be regrown in future years.
Being more careful to make crosses, and forcing hybridization seems to produce much higher yields in the offspring. Using varieties that produce high volumes of berries that are often selfed, rarely produce offspring that are high yielding for tubers. In fact, these varieties often seem to only produce middling results as parent unless I am using their pollen to pollenate other varieties.
I can modify my goals or plans to be far more selective with which potatoes I allow to be parents of TPS I grow out. But this seems to be in some contradiction of principle with the theory that abundantly fruitful potato plants should eventually lead to producing high yields. I will point out that I do think these goals are not easily aligned, and possibly cannot be aligned.
There is a case to be made for wanting potatoes that are all of hybrid offspring (and yes I know in theory even selfed potatoes are hybrids of a sort, but all are not equal). This makes a good deal of sense, assuming it is a case of hybrid vigor. A minority of selfed plants might also produce equally, but the percentage of good yielding seedings from selfed TPS is much lower. Plants that produce a high percentage of selfed berries tend to produce low percentages of good yielding potatoes, and low percentages of seed that is open pollinated.
What I am moving towards is using only specific, proven varieties to pollinate other varieties. The longer I have been growing out TPS, the more I find I am selecting not for production in their seedling year predominantly, but production when grown from tubers in their 2nd year. It is becoming increasingly important to me to identify which varieties are of highest value in using as parents in crosses, and less about just wanting a larger diversity of plants that are open pollinated or selfed, or produce high volumes of berries or TPS. I do want both, but intentional focus on parentage seems to be of higher value in breeding, than just broadly growing out TPS from a diverse mixture. Paying attention to varieties and record keeping with notes is becoming more valuable with potatoes than with any other crops I have set my hand to grown. A modern landrace of potato plants then, really, is built from varieties that have proven themselves primarily by yield and success in a local climate, and can be used as parents. That is not easily done without some semblance of tracking parentage and a track record that crosses multiple years and multiple generations of plants.
Some of this should be a bit obvious upon reflection, but it is not the direction I thought I was headed in when I began this journey with TPS.
Selection then, might be most usefully done with regard for proven parentage of useful tubers of acceptable yield, with those potato varieties becoming central to a breeding program.
Introduction of new varieties is done not just for the purpose of having a wide genetic base, and hoping for mass open pollination with other varieties. It is instead with the goal of identifying which varieties will be most useful as parents in future cross pollination.
My landrace, therefore, has become merely a genetic pool of plants that I have deemed to be useful, productive parents. Not really a landrace at all. This is very different from what I seen with other crops I have grown.
Up to this point I have not done much with potatoes, but I'd like to. After reading your post I have a few thoughts.
1. Im not sure breeding for very abundant fruit set will have plants that have good edible root yields. I think there is some degree of mutual exclusivity, but not completley. I think there may be a "sweet spot" where you get decent tuber yields and some, but perhaps not a lot of berry set. The plant only has limited resources after all. I would think a plant would tend to want to do one or the other but not both unless very carefully selected to do so. But even then you wouldn't get maximum yield potential for both traits at the same time. Only in the middle for both if your lucky.
Similar to trying to breed for perennial grasses or corn. They may have perrennial traits, but that probably means you take a hit on yearly yield or they become biannual. But is probably hard to get both in one plant.
2. Im wondering if self incompatible genes like Joseph's tomato project Is the way to go. Heterosis or Hybrid Vigour seems to be a major benefit for potato growing, so that seems very logical to me. I guess that means Diploids despite the tubers being smaller and that they grow slower.
But smaller potatoes is not necessarily a bad thing. Tiny foods are becoming popular at whole foods and sprouts like stores. There is a niche market.
3. I'm still attracted to diploids despite it being the harder way to go. One just probably needs to go for it anyway and try to avoid self compatibility genes.
I'm surprised this post has now been nearly three years without response. I'll dig this one up since it has a good deal of useful information, and answer with my thoughts on Andrew's thoughts.
Quote from: Andrew Barney on 2019-11-02, 08:03:29 AMUp to this point I have not done much with potatoes, but I'd like to. After reading your post I have a few thoughts.
1. Im not sure breeding for very abundant fruit set will have plants that have good edible root yields. I think there is some degree of mutual exclusivity, but not completley. I think there may be a "sweet spot" where you get decent tuber yields and some, but perhaps not a lot of berry set. The plant only has limited resources after all. I would think a plant would tend to want to do one or the other but not both unless very carefully selected to do so. But even then you wouldn't get maximum yield potential for both traits at the same time. Only in the middle for both if your lucky.
Yes this is exactly correct, though in most cases with small amounts of berries, the yield reduction is probably not significant. Studies have been done to remove berries from commercial varieties and yield results were negligible. A plant only has a finite amount of energy available and if too much goes into berry production, it comes with an adverse result for tuber yield.
Overall yield is a function of leaf cover of the soil over time. A large plant with larger soil surface coverage could be expected to yield a higher result of tubers than plants with smaller soil surface cover, but the overall yield per square foot or meter would not be different, except where length of the growing season contributes. Long season potato varieties can outyield short season ones.
QuoteSimilar to trying to breed for perennial grasses or corn. They may have perrennial traits, but that probably means you take a hit on yearly yield or they become biannual. But is probably hard to get both in one plant.
The main problem with perennialization of potato tubers is that diseases can overwinter in the soil This is a bad idea in general with any clonally propagated plants. Plus some tuber loss in the soil could result in uneven plant growth in the spring unless the grower is in a warm climate.
Quote2. Im wondering if self incompatible genes like Joseph's tomato project Is the way to go. Heterosis or Hybrid Vigour seems to be a major benefit for potato growing, so that seems very logical to me. I guess that means Diploids despite the tubers being smaller and that they grow slower.
Hybrid vigor is beneficial with potatoes. For many years, this is why most potato breeders from the mid 1800's until recently, and possibly even now, have not cared much about having male sterile clones. Male sterile clones make crosses easier because they do not need to eliminate self pollinated seedlings. Hybrid seedlings will more often outperform self pollinated ones, and too many generations of self pollinated seedlings tends to decrease fertility.
QuoteBut smaller potatoes is not necessarily a bad thing. Tiny foods are becoming popular at whole foods and sprouts like stores. There is a niche market.
Smaller potatoes do not necessarily mean yields are lower since yields are a function of maximizing soil coverage with foliage. But it is easy to force potatoes into producing smaller tubers just by planting closer together. Crowding encourages a higher quantity of smaller tubers than when seed tubers are planted further apart.