Sweet Potato Breeding Project

[reed]

There is still a capsule or two on the stems in jars but I'm declaring this year's TSPS crop officially over. Got two more 2YP this morning so up to 19 of them. Packaged them all up and will be sending them out in next few days. I kept about 1/3 of the total and planning to try to start about 100 next year, without benefit of any kind of stratification, I hate the thought that some might be wasted but I want to select for seeds that sprout without needing that. I'll be happy if I end up with ten plants. Don't know what I'll do with them if I get more, guess I'll plant them crowded. Gonna freeze about a hundred for back up.

I will also be starting, I think, six or seven different kinds from slips. I'm gonna try to run a TSPS factory next year.

The cut stems have rooted and are growing just in water, thinking I will pot some of them up and see what they do in a south window over winter and maybe sample them as a fresh green.

This has been a really fun project, hope it works good next year too. I didn't do much of anything except watch bumblebees and check for seeds everyday.

[rangardener]

Nov 23, 2016 16:45:25 GMT -5 imgrimmer said:

Kangkong was difficult to cultivate for me. Never had enough leaves for a meal. I think it is much more heat loving than sweetpotatos.

This is a thread about sweet potato breeding, but since imgrimmer mentioned kangkong, I guess it is OK for me to relay my experience in the cool summer of maritime zone 8 climate.

Ipomoea aquatica (kangkong, water spinach) is, like sweet potato leaves, another summer favorite of ours. I had no luck with seeds (which are banned here anyway) but can buy them in Asian grocery stores easily, rooting is easy. I grow them in plastic buckets with no drainage holes. They do love heat: once I put a small container of water spinach in mud inside a translucent plastic box sat in direct sun light, the water became literally hot in the afternoon (so hot I could not keep my finger tip in it), and the plant was perfectly happy. Strong sun light seemed even more important than heat. Growing in my “greenhouse” (very old roof, quite dim, reached 120F in summer) they were fine but did not do as well as growing right outside the greenhouse (better direct sun light). Buckets of water spinach in mud there got us good water spinach every week the whole summer.  In contrast, sweet potatoes do fine in my dim greenhouse.

Reed, I am following this thread with great interest. I have been making progress with growing sweet potatoes in the past few years and I hope to see new things coming our of your project!

[reed]

rangardener, I hope to have lots more seed to share next year. If every seed is a new variety it is a terrible waste not to give every one a chance to see what it might turn into but I am very limited on space. If things go well I'll be needing more collaborators. 

I didn't see a lot of variation this year between the 1YP and 2YP except in seed production. A single 1YP plant made 150+ and two 2YP plants made less than 20. Other than that they looked very similar. I guess 3YP plants should segregate more, especially since two more pollen varieties are involved. 

[reed]

I'm really looking forward to next year in hopes of getting lots and lots more sweet potato seeds. I keep looking around the yard and garden for any way to expand space for the project. I only have five of the big cattle feed tubs that they did so well in this year. They work good partly because they keep the plants safe from rabbits and you don't have to stoop over so much looking for seeds although staking would also help with that.

I have roots from nine varieties known to make seed and hope to have at least twenty plants from seed, so I need in the neighborhood of thirty tubs. I want to use my in ground space mostly for ones dedicated to food production although I'll certainly be checking them for seeds too. I'm trying, so far without success to find trust-able local people to take any extra seedlings to grow out to see what kind of roots they make and by giving each person only plants from the same mother to test for self compatibility.

I suppose I should give some priority to any 3YP plants that I get but still to early in the project to be too discriminatory.

[reed]

I'm glad I posted here about the TSPS cause I didn't keep many other records. I went back through the notes did keep ant the posts to see how to proceed this year.

Last year:
Planted seeds on April 17, first sprout on April 22 - set them out in early June
Don't remember for sure how many I planted but think it was about twenty or so and three sprouted. I'm calling germination rate at 10% even though it may be a little higher. 
Planted Patriot and Hong Kong from Sand Hill in mid June
First flowers appeared late July into early August
Many early flowers did not set seed. Good seed set began  in early to mid September ** (seed from seed) plants bloomed early and abundantly but few seeds resulted
Most seed was produced late September through October. 
The earliest seeds came from the Sand Hill varieties Patriot and Hong Kong and a large percentage are likely crosses between those two since the vines were intertwined.
**I dabbed around a little and I saw a few small bees and flies but vast majority of pollination was by a particular species of small bumblebee. They are very methodical in visiting the flowers, moving from one to another nearby. Intermingling vines facilitates crossing.
The stems I clipped and brought in in early November finished making seeds and are still alive.  

For this year:
Poor seed production on the plants from seed is concerning. I will certainly grow the (seed from seed) but will not replant cuttings or start any slips from those roots. I don't know if poor production was environmental or genetic but since they all grew together I'm guessing genetic and I don't want to encourage that tendency. I intend to cull any that do that this year. 
I'm gonna start slips from Patriot, Hong Kong and all the ones I got in trade but not the 1YP or 2YP roots. I'm watching how they all keep and one of the ones from trade is kind of withering up a little, I don't want a non-keeper trait so may just let it croak. All the others look great still.

I plan on planting a row of all the slip started ones in the ground, alternating varieties so the bees carry pollen from one to another.  
I'm gonna plant all the traded seeds, and all the back up seeds from 2015, a total I think of about 30. Excepted here are the ones that grew into non producers this year, I may discard them.
I'm gonna plant about 100 P or HK seeds this year, about 50 1YP and all ten of the 2YP for total of about 160. Based on experience and without any stratification I expect in the neighborhood of maybe 20 plants. I'll plant them in large pots close to the row in the ground. 
I want to test for self compatibility but don't have space. I think I can work around that by cutting stems with unopened flowers to hand pollinate inside. 

*****To folks I sent seeds too***
I don't have a clue about the problem with the seed grown plants not making seed. Most of you are more knowledgeable about plant breeding and genetics in general than I, so you can make your own judgement and feel free to chime in with opinions if you would. That said, I believe that all the 1YP  and 2YP seeds I sent out could carry that trait, assuming it is genetic but a lot are also crossed to P or HK this year rather than selfed like the parent plants were so who knows. Most of the P or HK are crosses between those two so I'm not worried about them. To those of you like me, new to this plant breeding business as I stated earlier, I plan to cull any plant that blooms a lot but doesn't set seeds. 

I'm excited to get going on this again this year and can't wait to see what every one else come up with. 

[caledonian]

If I might make a suggestion: there's a technique for shading chayote vines to induce flowering and fruit set which might be useful in inducing the sweet potatoes to flower. But it involves moving large artificial shade boxes at set times each day to give the plants precise amounts of light and darkness; I think it might be too labor-intensive for most people.

[walt]

I've used 30 gallon barrels to make plants flower out of season.  Zea diploperennis, Helianthus maximillianii, and others, I think.  I'd take the barrels off first thing when I got to work at 8 AM.  I'd put hem back on just before leaving work at 5.
To use barrels on sweet potatoes, I think you'd have to trellis them.  Let them climb a roll of chicken wire or something.
Garbage cans might be cheaper than barrels.
I don't think all sweet potatoes have the same response to daylength.  I'm pretty sure they don't.

[reed]

I can say for sure that not all sweet potatoes bloom at the same time. Last year most of mine started in earnest about a month after summer solstice but others were later. I'm also not sure that growing them in a more shaded spot or moving potted ones there might make them bloom earlier.

My breeding efforts are actually more selecting and less breeding. I want things that don't need me to do too much extra stuff in order to make a crop and seeds. My general philosophy is if a crop won't do that then I won't grow it. Not that I won't make exceptions at least in the first couple seasons.

I was actually pretty surprised that sweet potatoes seem to one that is willing to cooperate with me on that.

[reed]

It'll be time pretty soon to get sweet potatoes going so I got out my saved roots that I hope to start slips from. For the most part the seem to be keeping pretty good, some better that others of course. 



The first one on the left is what I call BnG cause it is one my aunt and uncle have grown for a long time, I suspect it is a know variety, I just don't know what. It's late as far as seed maturity goes but keeps exceptionally well and tastes great. I have I think five seeds from it but several more were on a stem that the rabbits got, I want to keep it's genetics if I can. The purple on to the right is Hong Kong, it made lots of seed last year and early on in the season, I like that. I may have messed up on the next two, at least one of them is Patriot, hopefully both are but one is missing it's label and they look different so I don't know for sure.

The skinny ones are 1YP and 2YP. 2YP grew from a seed and I believe it's parent is the same clone as 1YP. I also believe 1YP may be self compatible. 2YP bloomed profusely but set almost no seeds last year. I will be planting those seeds but am culling this root. 1YP set abundant seeds last year so I will try to get slips from it but assuming I get a decent amount of seeds to sprout I will cull it also for space considerations in favor of seed grown plants and plants with better roots. 

The four on the right are Bonita, Nordic White, Mystery Jet and Purple. They and some of their seeds are from a trade. As they are know seed producers I hope to have both slips and seedlings from them in the patch this year. 

I'm gonna start more selection this year too, assuming I get good seed production. I'll be saving seeds separately according to when they mature. I think I'll make a cut off of late September and keep them separate even if they came from the same plant. I kind of wanted to keep better track of individual mothers too but don't think that's really possible or actually even all that valuable. Plants have to be in close proximity I think because of the methodical way the bees visit the flowers so the foliage will be all commingled anyway.  Unless one plant is distinctive from another I won't know who the mother was anyway and not sure I really care. 

If things go well this year they should be mixed up enough to just forget about variety names and start a whole new selection process based on quality root, reliable seed set and good tasting leaves and shoots. I wonder it it might be possible to develop a stain that is self compatible within the variety but not the same plant. That is probably beyond my ability due to the large number of  isolated trials that would be needed. I just don't have space for that. 

[farmermike]

Mar 5, 2017 8:11:57 GMT -5 reed said:

The skinny ones are 1YP and 2YP. 2YP grew from a seed and I believe it's parent is the same clone as 1YP. I also believe 1YP may be self compatible. 2YP bloomed profusely but set almost no seeds last year. I will be planting those seeds but am culling this root.

Very inspiring, reed! I have a small amount of TSPS planted under grow lights on a covered porch. What does the YP stand for?

[reed]

That's just what I used to keep those two separate. 1YP is a clone, first year purple, 2YP second year purple, grew from its seeds. (I think), I say I think because the 2YP seeds were produced in 2014 from a different plant. I think it was the same clone though because it looked exactly the same and came from the same green house.

I think 1YP and maybe 2YP could be self compatible because in 2014 there was only one sweet potato plant on the place. Also, last year the 1YP plant was on the edge of the patch and farthest from the others yet it produced seed evenly. I'm very interested in knowing for sure if selfing is really going on and may grow a plant in isolation this year to test it. On the other hand I do not want plants like last year's 2YP that bloomed a lot but didn't produce seeds which is why I'm culling the 2YP root.

Possible self compatibility is the biggest reason I'm keeping the P plants around but I'm starting a lot of seeds this year and if I end up with a good number of plants I may cull them all in favor of the plants with earlier seeds and larger roots.

[reed]

Wow, it's almost time to get the sweet potato seeds and slips going for the 2017 season. I was only able to locate 5 more of the big tubs so that that brings me up to 8. They are not really necessary, it's just easier to check for and harvest seeds if they are up off the round. I'll compensate by trellising the ones planted in the ground. Also going to experiment with some in smaller, just 3 gallon pots. I suspect that might stress them and promote flowering.

The small pots will also be easily mobile so when I see the flowers of wild ones (I. pandurata) I can just take a potted one and set it with them for the bees to do their thing. I know odds are against it but I really want to cross these two species so I'll also be doing hand pollination in both directions. This year I'm gonna plant some in a little more orderly way so I hopefully will have some seeds where the mother variety is know but the main patch will still be a tangle.

I think maybe the tangle approach may actually be more conducive to pollination because the bees tend to move from one flower to the one right next to it so stems of multiple varieties tangled together makes for more successful pollinations. If they have to fly two or three feet between plants there would still be crossing but not as much.

Hard to believe how I went from not even growing sweet potatoes most years to being almost obsessed with them. With tasty nutritious roots that are easy to store, nutritious leaves that can be grown in a south window all winter and tolerant of, almost preferring drought and heat they deserve a much larger share of attention, effort and space than I used to think. So, for this year I will assign as much as 1/4 of my total growing space just to sweet potatoes. I'm not growing for root production or root trials at this stage so they can be overcrowded.

This is gonna be fun, if things go well I'll have lots of seed to share and next year will start the process of seed from seed only. Trials and evaluations of roots can take a higher priority after reliable seed to seed is established. Hum, wonder how long that might take?

[Joseph Lofthouse]

I planted my sweet potato seeds a week or two ago. Thanks reed. I forgot to pay attention to them until today. In addition to these seedlings, 3 of 4 seedlings from last summer look like they barely survived the winter indoors.

[gilbert]

I'm going to be working on breeding sweet potatoes this year, as part of my larger perennial Colorado tuber project. Is there a list online anywhere of varieties which are known to flower profusely?

[reed]

Those look great Joseph Lofthouse . What is the germination rate? Did you do anything like acid treatment or scratching the seed coat to encourage germination? I will probably do the second one on the seeds I got in trade cause I have comparative few of those but  won't do anything on the others as I want to try to select for lines with easier to start seeds. Which group are those from or are they just mixed? The solid green  look like maybe PorHK, the purple one does not look quite as purple as last years P plants so maybe it's a cross. In any event it's great to see them, looking forward to seeing some Utah produced TSPS. 

gilbert , I don't know of any specific lists. I went through Sandhill Preservation's rather large list and found the varieties Patriot and Hong Kong and grew them with a couple locally acquired unknown varieties. Seeds I designated as PorHK had one of those two as the mother plant. Sandhill has another variety described as a good bloomer called Red Resisto that I want to add in. It either wasn't available or I missed it last year.