Breeding Sweet Potatoes (turning them into a seed grown annual)

[reed]

Well, a little bit of a disaster has struck. When I put my saved roots in the cold frame as in the photo shown in earlier post it was still pretty chilly in the mornings, but they took right off. Then it got warmer and I went ahead and took off a few slips, just from three or four roots and planted one of each thinking it would probably get colder again, and I wanted to see what effect that would have on them. Unsurprisingly it slowed them down but did not hurt even though one morning had light frost on the car windshield it didn't kill or even damage the plants.

Meanwhile in the cold frame the others were doing nicely, and I was planning to set them out in a day or two, but it got a bit warmer and I forgot to open the cold frame one morning. The cold frame had been recently remodeled with new tape to seal the seams and with a foot deep bed of composting material providing a little heat from the bottom, and a fully sunny day with a high of about 85 F, my sweet potatoes and the slips they were making cooked. I held out hope they might make some more slips, but the roots themselves were actually cooked. They were soft and dead.

I was only able to save a couple slips from one root so those I planted earlier and those are the only ones I have. Five of the nine roots in that other photo, five unique examples of ipomoea batatas were lost. Fortunately, one that I had planted earlier is our favorite for cooking and it is doing fine as are the other three. All of them are fine sweet potatoes that all have most of my preferred traits. It's just that I won't have extra slips to maybe sell this year.

I described it a "little bit" of a disaster because that is all it is, maybe no disaster at all really because one of the main objectives of this project is a guarantee that a crop failure, even a total one which this isn't, is recoverable the next season.

Except all along I have selected for fast maturity, seed to harvest in 100 days or less and I have plenty more season this year, no need to wait till next. So, I got into my seeds and planted forty in a row in the ground. These seeds are top line seeds mostly from the very plants that were lost. They just sat there for a while until it finally rained and twenty-seven of them popped up immediately and a few more since then. A little bit of a disaster is that I only have twenty-five pots ready and four of them are already take.   

And then on a whim I planted a couple hundred low grade seeds. These are seeds that after harvesting last year were later picked off the discarded vines. Mostly little brown and wrinkled things, not the nice fully formed black ones. Drying on discarded vines without fully maturing and even after a frost or two I figured I would be lucky to get half a dozen plants but apparently what I thought were bad seeds and usually didn't mess with aren't bad at all. I suppose they are responsible for the volunteers that I find each year.

Germination on the low grade wasn't the two or three percent I expected but more like 25% or more. This photo was taken a couple days ago and a few more have pooped up since then.



Now I guess the disaster is that I have probably wasted a bunch of seeds because all together I have close to a hundred and only space for about twenty. I do have some more pots but not that many but I don't have enough compost and stuff to mix up more soil to fill them and I have a near religious objection to buying dirt. I might do that though, so I don't have to discard them because chances are very high that plants as good or better than those I lost are in there.

Maybe this is more of an opportunity than a disaster. These low-grade seeds also (mostly) came from those same superior plants. If I can pull off keeping them all maybe I can arrive at a measure of probability that any one new plant will have all or most of the desired traits. Another possibility is that if I can study them close enough maybe I can get better at finding observable traits that will indicate early on which ones are likely to make nice big roots and which ones are more just ornamental. 

On the ornamental side both "Likes to Climb" and "Ms. Bloom" are doing fine. I had already planted several of them here and there and those in the cold frame died back from the cold frame turned sauna but immediately shot back up from the roots. I had thought of planting some older generation seeds looking for more ornamentals but under the circumstances won't be doing that this year.
   

[reed]

Sweet potatoes are mostly transplanted and looking good. I ended up with 30 from the grade A seeds in my 7.5-gallon pots and 15 from the grade B seeds in 3-gallon pots. I left half a dozen of the grade A sprouts in the ground, but they are being smothered by okra now. I might try to find a new place for them too but not worried about it right now.  I made a nice well amended bed and put another 35 from the grade B seeds in there. They are a bit crowded but it's the best I can do. There is another very nice dozen or so of them left for now in the big tub I started them in. I also scrounged up ten mismatched pots for some volunteers that I found here and there but are still some more volunteers.

I have another smaller spot that I was going to turn into a new onion patch but since I'm already so invested in the sweet potatoes this year, I might use it for the leftovers. I'll leave three or four in the big tub where they sprouted and have another big tub currently drying down some peas that can take three or four.

A lot of interesting things showed up in the grade B seeds. They are from the same plants as the grade A but something weird happened. I don't want to say that mutations were caused in the lower grade seeds, but it seems like that might be the case. There were three what I call "vampires" in the bunch. I've seen them before and they apparently don't know how to make chlorophyl. They also die fast if exposed to full sun, I didn't mess with trying t save them. Probably a dozen more had just one or fused cotyledons. I have also seen extra cotyledons in the past, as many as five but none of the showed up this year.

Often when the cotyledons are single or fused the true leaves sort of bust out of the stem below the cotyledons and the plant grows normally after that. I planted a few of them in the in-ground patch and they just look like normal plants now.

I remember when I did lots of research, I found that they can mutate or revert to the mother phenotype in the first few seasons of cloning. I won't say I didn't believe that because I think the university plant witches know what they are talking about, I guess I didn't expect to actually see it myself. Turns out it isn't all that uncommon like when the plant I call Ms Bloom grew a different color root. I think it applies not just to sweet potatoes but to most plants that are generally cloned like apples. That's why a new one has to clone true for a few years before it can be presented for patent, not that I want to patent anything.

I lost the saved roots of Ms Bloom. Not from failure to produce slips of anything, I mean I can't find them. I'm not the only one that gets into the storage bins so my best guess it that we must have ate them.  Kind of a bummer but as they say, stuff happens.

I'm watching one those with the fused cotyledons this year because heart shaped leaves busted out in the center but another stem with "maybe" ivy leaf bust out below. I say maybe because it is just one leaf right now and could be just an injury or something. If it turns out a single plant really has two different leaf shapes it will be fun to grow it out, but I don't know that there will be anything really special about it.

All of the cloned plants are in big tubs and doing nicely. I've got about twenty each of my ornamentals, Ms Bloom and Likes to Climb stuck here and there all over the place. They are in varying conditions depending on how well the ground was prepared and how hard it is to keep them watered.

I almost forgot that lots of seedlings and clones are growing flower buds. Several started with just the first or second set of true leaves. I've seen that before but not to this extent. I don't know if it is genetic or environmental or maybe a bit of both.     

 

[reed]

I've neglected to update on my sweet potatoes lately so made a little video this morning. I accidentally refered to my ornamental plants as culinary, so ignore that.

[reed]

Just uploaded another little update about my sweet potatoes.

[reed]

It's too early to say for sure but observing my sweet potatoes this year they certainly do better with some shade. At least they are much easier to take care of. I sat and watched them for a couple hours the other day and those that get full sun until early afternoon and full shade by later in the afternoon never wilt from the heat.

Those in full sun all day are wilted by midafternoon, especially the ones with darker colored leaves, no matter how much I water them. By evening when they also fall into shade you can literally watch them perk back up. By morning there is no difference. It's a big difference though in how often I have to water them. I have clones of the same ones in the different spots, will be interesting to see at harvest time if there is a difference in root production. If not or if it is just slight, they are all going into more shade from now on.

When I first started with them, I thought that being tropical in origin they probably wanted full sun. Looking back that was a silly assumption. I'm sure there is lots of shade in the tropics and probably lots of plants there prefer it.   
   

[reed]

I've mostly just been wandering around visiting with the sweet potatoes for the last several days. After much pondering and some great consultation, I think I have an idea on how to proceed next year.

I have those three clones that survived the easy bake cold frame incident growing together now semi-isolated from the others and want to expand on that idea next year. It will depend of course on what I find underground with all the newly sprouted plants at harvest time. Those seeds came last year mostly from the same original nine clones I had in the cold frame.

The survival of those three I still have isn't because of genetics. It's because I had taken some slips already and put them out early knowing they might get frozen, they didn't. When I forgot to open the cold frame that morning and it hit 85 F with bright sunshine all of the slips and all of the roots died. The slips were fried that evening, and I thought the roots might sprout more slips but within a week or so they all turned dark color and started getting soft.

Anyway, out of those almost 100 new plants I hope to come up with a few more of what I'll call breeding groups or compatible groups or something like that. Seeds from those three which I guess I'll call breeding group #1 will be saved separately from all the others, I may even separate those from each individual clone. I may or may not grow those seeds the following year. If I end up with more collections of three, I will only grow clones next year, no new seeds at all except for what might come up volunteer. I imagine there will be quite a few as both the in ground and in pots plants are terribly overgrown and intermingled. It will be near impossible to find all of the seeds and I don't intend to even try. I'll just watch for seedlings next year and move them appropriately away from the breeding groups.

I have close to twenty of my big tubs which can easily hold three plants so my breeding groups like the one this year will be sets of three different clones in the tubs and isolated from each other by forty to fifty feet. That's nearly far enough I think but there will also be such things as runner beans, dahlias and corn separating them. Any pollen sneaking in from one of the other groups will be minimal.

I'm going with three per group because I don't know the compatibility preferences of any one plant and I think it is possible that some plants might only be compatible with some other particular plant(s). Just two plants in a group have a higher chance of incompatibility, four plants make it overly complicated for continued work of eventually answering some questions about any particular plant(s) compatibility preferences. It's possible that self-pollinating plants could be identified as well but in the near term, I'm looking at narrowing it to polyculture but not mass polyculture, at least for a couple of years.

Assuming the breeding groups goes well, seed from those groups will need to be grown in 2028 to confirm that they reproduce acceptably true to type and continue to be cross-compatible. On second thought I will grow seed from breeding group #1 next year, it has a head start.

[reed]

My sweet potatoes are moving on, starting to make seeds but I haven't collected a lot, just too lazy, I guess. Have to get on that though because September is generally the seediest month, even into October as long as frost doesn't threaten.  I've taken a lot of photos, just haven't put them on the computer yet. Made a couple videos too but when I played them back had screw-ups I didn't like so they ended up on the proverbial cutting room floor. I don't script my videos and I don't edit them, if they come out wonky, I just have to start over.

It had been hot and dry, but I kept them watered, so they looked good already, but it finally rained a couple weeks ago and stayed cooler, just lower 80s for a while with ample water and they went crazy. Several are totally out of control, sprawling across the paths and invading beds on the other side. Hot and dry again now, so I'm back to watering every couple of days.

I have always avoided mentioning much about the genetics, lest I give the appearance of knowing what I'm taking about or demonstrating that I don't. I've been digging into that now and learning and relearning lots of things. I batatas is a hexaploid species, and it evolved from a cross between two different species, and it picked up a bit of genetics from a bacterium somewhere along the way.

There is a bit more known about them now that ten years ago when I first read up on them. Seems a very well-funded outfit is putting them under a microscope, so to speak but I won't go on more about that just yet.

To understand what exactly what hexaploid means I had to go back a bit to what diploid really means and came across some other terms that if I ever knew, I had forgotten. Something confusing was the difference between a diploid species and diploid cell but I think I have that down now.

Then you got your haploid cells and something called meiosis. This is where sweet potatoes as compared to a diploid species go a bit off the rails of predicting what will happen when a new seed sprouts. Diploid, no problem, a cell undergoes meiosis and produces new cells, each with just one half of the DNA strand. I'm unsure of the proper term for that half, so I'll call it a string, and two strings make a strand. The same chromosomes are lined up in the same order, and the strings are the same length so poof, when two get together they combine into a DNA strand and new seed. The short, I guess of sexual reproduction minus the many nuisances. I wonder too, not that it matters, if a single DNA string is basically the same thing as RNA.

So, in a diploid species its theoretically fairly simple. Genes are easily identifiable in a lab or over a much longer time just by observation and selection. But a haploid sweet potato cell (I'm guessing) has three of the individual strings each with 45 chromosomes instead of one string of 23, like with people. Does the term haploid even mean the same thing whit a hexaploid, since we're dealing with three strings instead of one? Three strings from each parent make six strings, six copies of each chromosome instead of two.  What a mess.

The new research I found complicated it even more. It appears that with most species that originated from an interspecies cross the chromosomes are arranged in such a way as to be identifiable as to which species they came from. I don't remember the term for that, but sweet potatoes don't follow it. In sweet potatoes they are all mixed up. Attempting to sort that out in the lab is what this new research is doing, I guess.

[reed]

Well, I've been reading on the topic some more and I'm pretty sure my last post is not entirely accurate if it's accurate at all. It appears that meiosis in a hexaploid species is way more complicated than in a diploid, way more. It seems that meiosis in any polypoid, of which there are a lot more than I realized is a whole different critter than in diploids. Lots of interesting stuff about wheat and kiwi came up in my searches.

In any event I'm pretty sure that's the root of issues with breeding sweet potatoes. I think sexual incompatibility including male and or female sterility and spontaneous mutation are the two most important. I've tamed the incompatibility problem to a large degree just by observation and selection, but I doubt it will ever completely go away and it's probably really best that it doesn't. The mutation will probably also always be in play. I like the mutations. It's fun to see new phenotypes just pop up by surprise once in a while. 
.

[reed]

I finally got a new quick little video of my sweet potatoes, and I did a couple little side experiments this year that I mention there. One is in what I'm calling breeding group 1 and it is just seeing how fast a sweet potato can produce roots. They were planted as no-rot cuttings on July 10th and are growing very well. I'll hold off on harvesting them until last to give them a bit more time. The vines are bigger than I expected they might be at only about sixty days.

Here is breeding group 1 on July 10th


And now, on September 6th


And the little video I made yesterday is below. I mentioned that I was going to start harvesting soon but have moved that up to today. Digging around in the vines yesterday I discovered quite a few capsules seeds had already shattered and lost seeds and a lot more pretty well advanced.  I'll just save any dry ones I come across and clip pieces with lots of seeds and put them in water to finish. Some of those that are already lost will volunteer next year but I'm not planning to start any new ones. I want instead to just focus on establishing the compatibility groups from clones. 

I don't think sweet potatoes will ever breed true and there will always be some percentage of new sprouts that do not have all of the preferred traits but by establishing the breed group(s) I think I can bring the percentage of that to a good level. Then I can release seeds from these groups and folks can plant some seeds, find some they like to clone and just save the seeds year to year. That way if something ever happens and live clones are not available anymore; they can just get out some seeds and start over. Or if they want, they can continue breeding them year to year.

I'm looking forward to the first option for myself, just clone my favorites year to year and stash the seeds, just in case.

[Carol Deppe]

Do these grow fast enough from cuttings to mostly suppress weeds? Looks like much of the planting is a cheerful jungle.

Are these in full sun or partial shade?
I think I've read about sweet potatoes being interplanted with corn in tropical areas. What do they prefer with respect to full sun vs partial shade in Indiana?

[reed]

Do these grow fast enough from cuttings to mostly suppress weeds? Looks like much of the planting is a cheerful jungle.

Yes, they do especially if the soil is good and they get plenty of water which these did. About the only weeds that found the sun above the sweet potatoes were a couple of tomatoes that I pulled out and a cowpea that I just left alone.

Are these in full sun or partial shade?
I think I've read about sweet potatoes being interplanted with corn in tropical areas. What do they prefer with respect to full sun vs partial shade in Indiana?

These are in full sun, but I've kept them well watered ever since planting. Overall though, I think they do better in considerable shade. They are certainly easier to care for in shade as they don't need as much water. I think full sun in mornings and full shade in the afternoon would be ideal, but it is the water that makes the big difference.