I'v established a patch of Ipomoea pandurata with intention of attempting an inter-species cross with Ipomoea batatas. Turns out though that Ipomoea pandurata is pretty interesting on it's own so I thought I would give it a thread of it's own in case anyone else works with it and maybe has some experiences to share.
My research into it indicates that it is rather rare, it isn't. I'v found a number of wild specimens. It is also described as being similar in some ways to I batatas specifically in that is self-incompatible, again it isn't. But there is something weird about it. The very large plant closest to my house made lots of seed in 2016, 2017 and 2018 but none this year. All of the other plants I'v located made no seeds in previous years but two have seeds this year. Another interesting thing about the previously seedy one is that it is way smaller this year.
Couple years ago I managed two seeds that I think were pollinated by pandurata but they did not sprout. Since the plant close by didn't bloom much this year I wasn't able to collect much pollen and I doubt my recent attempts took either.
As far as sprouting the seeds they are pretty easy, just direct sown or in the cold frame. I do think that unlike batatas they benefit from cold stratification but if you keep your seeds frozen that takes care of that anyway. Seeds planted last year (not cold) treated did not sprout but near 100% sprouted this year. Some started in cold frame transplanted easily with no losses and I couldn't tell a difference between them and the direct sown. I don't know how long it will take a new plant to bloom but suspect it might be a long time so it may take a while till I have the two species growing conveniently close together.
My patch is out by the mail box at the end of the drive where I'm in hopes they will just go wild and grow up into the weeds and trees like the wild ones do. It's too far from the water source and since they are wild I figured they should be tough enough to fend for themselves. By appearances that is not they case, it very hot and dry there and only one has any live leaves left at all.
But another very interesting thing is I had some left overs from the cold frame that were just set out on the ground and in the pot they were started in and they apparently dried up and died weeks ago. I dumped that pot yesterday and found roots about as big around as a sharpie and if they weren't all curled up would be probably a foot or more long. They are funny looking each one starts out a little bigger just under the stem, goes down three or four inches and forks like legs. Maybe that's why their called man roots. They were easy to peel, just scraped it off with thumb nail. Taste, raw was largely absent but with a hint of sweet. In any case I can now say I'v eaten wild sweet potatoes. The ones in the ground grew much much larger so I'm imaging they also have much larger roots, I think I will just leave them be though and maybe dig a couple next year. It's encouraging I think that the big roots are directly under the central stem so you don't have to dig a crater to find them.
I put the dormant, rather than dead roots, they each have little bud or two on top, in a shallow pit with a little water and dry leaves on top to see if they keep over winter that way.
I'm wondering as a food crop if a person might grow them from seed, let em go for a few years, starting new ones each year too. Gonna have to get a better handle on issue of why they do or don't make seeds and why the do sometimes and sometime not. I haven't had any luck cloning them from cuttings, they are very different from batatas in that respect.
(add) O'yea the inside of the inside of the roots is snowy white and 24 hours after eating one, no ill effects.
I noticed that wild Calystegia (a european native Ipomoea relative) is a very bad seed producer too. I visited a patch with wild Calystegia pulchra for several years in search for seeds. There were barely any to find and these have a bad germination.
When I check seed capsules of the more common white Calystegia there are often none to find.
I always wondered what that means. Interesting that pandurata has a similar behaviour.
In my research on sweet potatoes I'v come across mention of this several times in relation to other Ipomoea species. Most talks like they are just not self compatible but based on my observations at least with pandurata that just isn't true. They make seeds sometimes and sometimes not, some environmental variable must also be involved, it seems to me.
Reed,
You got seed from batatas x pandurata? I'm getting a pandurata population ready here, in their 2nd year all 3 of mine flowered and I'm harvesting seed. I'm going to try the roots soon. A batatas x pandurata would be really interesting and is high on my list of wide cross attempts. Are you gong to use batatas true seedlings to pair in the cross? You might want to cut some of the styles of the batatas once you set it up because it's tricky for the pollen to get all the way to the ovary.
Wishing you success
I pollinated several batatas flowers with panurata pollen but only got those two seed which did not sprout. Not 100% sure they were crossed cause my technique is a little sloppy and a bee might have sneaked in there too.
That's great your pandurata are flowering in their second year. If mine do that so I don't have to drive somewhere to collect pollen I'll be able to make lots more attempts and also the other way, with pandurata as mother.
I have a pretty good assortment of my own seed grown batatas that easily flower, I'll use them in my attempts. What do you mean by cutting the style?
About the strange (in-)compatibility of pandurata, this what genus expert Ron Kushner had to say in a recent FB post: "Cross fertilization tends to work if the plants are from significantly different populations, although plants within the same general vicinity tend to be incompatible also for most of the time , although the cross incompatibility may change over a period of time that only the plants seem to know , hence the mysterious part of the story." Nevertheless, more genetically diverse pandurata more frequently produce more seed. For the amount of flowers my 3 plants produced, the seed harvest had been a fraction of that.
Reed did you come across the Russian (of course they did it first) research on batatas x pandurata? https://www.docdroid.net/AKiHsfR/101093-at-oxfordjournalsjhereda103982.pdf?fbclid=IwAR1NIfdIlxt-7hdwVFWXm6RUVys2fOqcglFqSzVb56mgZ5c4K4TOZgbT5D0
It looks like pandurata as a mother fails, and batatas x pandurata is successful at around 2%. Not really much information about the hybrids themselves.
Cut style pollination, also called stump pollination is where you chop of the stigma and a part of the style somewhere above the ovary. It's just a hypothesis that it could help in Ipomoea, based on observations of pollen tube pathway irregularities and growth tube restriction of batatas.
Also promising is the application of growth hormones to the flower stalk after pollination. https://rd.springer.com/article/10.1007/s10681-009-9967-7?fbclid=IwAR3OK-YlV0zqPYc8VdsWhjYKFnjOSRlZjOV3ZNvk4JR7AeUgNjje403Gn7k
"To overcome interspecific cross-incompatible barrier, we applied 100 mg/l GA3 + 50 mg/l 6-BA to the stalk of the pollinated flowers. The treatment was conducted for seven consecutively days for good fruits and seed sets." These crosses are more genetically distant than pandurata, and despite that pollen fertility of the F1 approached 80%.
I won't be gardening next year, but hope to set up an experiment after that. This fall I'm going to divide one of the pandurata roots in sections and see if that works for propagation.
Edit: I see you tried vegetative propagation already, too bad it didn't work.
I had not seen that paper before, interesting reading. The 2% success is in line with other papers I'v seen. Have to wonder about lack of follow up on what happened after that.
I din't try root divisions of the pandurata, just cuttings. They failed to sprout roots in water, in soil, in sun, in shade. I don't know of anything easier to propagate that way than batatas.
Which other papers talk about this cross? I only know of one which references this one.
Have you seen this report on the edibility of leptophylla? Makes me want to try this one as well.
https://www.pullupyourplants.com/unusual-garden-plants/2018/2/12/bush-morning-glory
Descriptions like "crisp and sweet" are said to apply to macrorhiza which is supposed to be comparable to jicama, and can be eaten raw. The three are closely related — leptophylla, macrorhiza, and pandurata.
O'goodness I have lots of papers saved but there is one of my favorites cause it talks a lot about inheritance of various traits in batatas, most of my work has been with batatas.
https://digitalcommons.lsu.edu/cgi/viewcontent.cgi?referer=https://scholar.google.com/&httpsredir=1&article=1843&context=gradschool_disstheses (https://digitalcommons.lsu.edu/cgi/viewcontent.cgi?referer=https://scholar.google.com/&httpsredir=1&article=1843&context=gradschool_disstheses)
It's rather lengthy and only mentions inter-species crosses kind of in passing.
QuoteAlmost complete failure has resulted from m o d e m attempts to hybridize Ipomoea species. Toutine (104) reported capsules formed from crosses of batatas X JL. fastiglata. _I. batatas X _I. macrohyma. and batatas X I. pandurata. No further report as to whether these capsules contained viable seed was found
I know I've seen it other places too, will do a little more digging.
I'm not at all familiar with leptophylla but after reading that paper I tracked down some seed on Etsy. May have to add it to my collection.
I don't know much about such things, never tried it before but I think I might try grafting next year. Assuming my pandurata vines take off good which I expect they will I can easily try grafts in both directions and see what happens. Supposedly there is possibility of gene transfer that way so maybe if that happened it would make cross-pollination more likely. Wish I had thought of trying it this year. Actually might not be too late, I can stop and grab some pondurata stems and see if they will take on a batatas trunk. Maybe I could keep it as a house plant, not likely I suspect but could be fun to give it a try.
Just looking up Ipomoea pandurata out of interest, says here it could be poisonous https://pfaf.org/user/Plant.aspx?LatinName=Ipomoea+pandurata
Richard, seems like I have seen that somewhere before. I only ate a small piece, maybe an inch and a half long by by 3/4 inch thick. There was no bitterness or other bad taste at all, just very mildly sweet. Still something to look into further.
That other ipomea that Chance mentioned is described in the link he posted as also being referred to as manroot and I've always heard that in reference to pandurata. Something else to research more this winter.
In the mean time mostly just for giggles, I dug up one of the smaller pandurata roots I'd buried and split it down the middle and inserted a shaved down stem of one of my best plants. Doubt much comes from but if the batatas stays alive for any time at all and without sprouting it's own new roots then I might be on to something.
Introducing I frankenbatatarata.
Richard, as I understand it the poisonous idea came because livestock don't browse the foliage. The mature foliage has a milky sap that is very astringent. The tuber isn't dangerous but I think if it was too mature the bitter components would cause digestive upset, but it wouldn't be palatable anyway.
Reed — fun! I would like to hone herbaceous grafting skills at some point. If one of them takes, there are a couple things to keep in mind depending on your goals. If you want to maximize the chance of sexual crossing, the idea is to graft the mother to be on the rootstock of the species that will be the pollen donor. If you want to maximize the potential for genetic transfer from a rootstock in the seed of the scion, that's where you use the mentor graft technique. You basically keep a lot of foliage on the rootstock and prune all but a couple leaves at the growing tip of the scion, eventually collecting its seeds. Ideally you want to use a scion in a state of plasticity.
Quote from: Chance on 2019-10-07, 05:24:33 PM
Reed — fun! I would like to hone herbaceous grafting skills at some point. If one of them takes, there are a couple things to keep in mind depending on your goals. If you want to maximize the chance of sexual crossing, the idea is to graft the mother to be on the rootstock of the species that will be the pollen donor. If you want to maximize the potential for genetic transfer from a rootstock in the seed of the scion, that's where you use the mentor graft technique. You basically keep a lot of foliage on the rootstock and prune all but a couple leaves at the growing tip of the scion, eventually collecting its seeds. Ideally you want to use a scion in a state of plasticity.
Thanks for the input, couple questions;
What is mentor graft technique?
What does state of plasticity mean?
Much to my surprise the batatas stem I used has not croaked. The large leaves look pretty bad, I probably should have removed them, but the small top leaves look perfectly fine. I'v been careful not to get any water on the graft so if they are getting any water or nourishment at all it is coming from the pandurata root. I'm scared to remove those larger leaves now for fear of disturbing the graft. something other than gorilla tape might have been better to secure the connection but that is what I had on hand.
I think I'm gonna try another one only use a different technique. I got piles of discarded batatas vines with lots of little roots that have buds or growth on top. I think I'll use a drill bit or something to excavate a little hole in the top of a pandurata root. Then shave down the tip of the batatas root to fit it. I figure it will give a better connection with less exposed injury as in the split part of the one I have now. If it works I may be able to keep it alive till next spring and if it blooms pollinate with pandurata.
Here are a couple mentor graft illustrations:
https://www.google.com/amp/s/www.researchgate.net/figure/Mentor-grafting-A-Non-graft-normal-plant-as-control-B-Mentor-graft-scion-leaves_fig2_270661829/amp
https://www.semanticscholar.org/paper/Historical-and-modern-genetics-of-plant-graft-Liu/1039b16b62b0ca3eb3fb83fcd6bc12b2b5ba28fa/figure/1
Mentor grafting is basically about creating a developmental asymmetry to maximize flow into the scion. Plasticity is most expressed in young hybrid plants—they might be throwing out different fruit sizes, flower colors, leaf shapes, etc. They are most susceptible to graft induced variation. It can also happen, to a lesser degree, when moving a plant to a different climate where it starts to have epigenetic changes and change phenotype. Or in a genetically diverse modern landrace.
You can use super glue to secure the graft as well. This guy does it with tomato: https://www.youtube.com/watch?v=5Fd6tBQTTAg
The hole method is called the hole insertion graft, commonly used in Curcurbita for disease resistant rootstock. There are videos of it on YouTube also. https://www.researchgate.net/figure/hole-insertion-grafting_fig1_316511579
Approach grafting is also good for herbaceous plants since they dry out so easily. Either way a humidity dome is pretty crucial for the healing stage of herbaceous grafts. As well as shade for a period and then gradually increasing light.
Look into vegetable graft healing chambers. http://edis.ifas.ufl.edu/hs1232
This video has some good tips for a veggie graft healing chamber: https://www.youtube.com/watch?v=9Mxy0HfgpKY
That's all very interesting. It had occurred to me to use glue but I was afraid of getting some of it between the graft which I figured wouldn't be good. The one video showed a little clip that looked like I might be able to make with a piece of drinking straw.
What I'm thinking now is I want to basically make a root to root graft with a chunk of batatas, perhaps containing one little bud on top of pandurata. I don't care if it grows much, just that the two heal together into one, maybe even letting it go mostly dormant over the winter. This might not be the best time of year to try such a thing but if it did work it would have all winter to become one plant and when new sprouts appeared on the batatas next spring the genetic transfer, if any should be maximized.
If the fused root is healthy enough next spring I might be able to remove any growing shoots and force new ones to sprout off the batatas. With the already known tendency of mutation in batatas who knows what might come from it. One paper I read speculated that the reason batatas does that is that unlike a potato tuber a sweet potato root does not have eyes. When it sprouts a slip it has to conjure it up from cells not generally used for that purpose in most plants. That particular paper was a little above my pay grade, when I come across it again I'll post a link.
Went out last evening and collected up some candidate batatas root and trunk sections. I figure it is important to try to match diameter as closely as possible so the respective types of tissue join each other correctly. I'll have to experiment on how to securely fasten them together. The glue method looks easy but still a little concerned about using it.
Not sure about needing the healing chamber, what I have in mind is so very different from normal vegetable plant grafts. I guess it's more like woody grafts like for fruit trees. Sweet potatoes like it hot though so if I put a plastic cover on I shouldn't need to worry too much about overheating.
Yea the glue technique seems most ideal with seedlings, but perhaps it can work ok in somewhat larger diameter plant stems too. If you search grafting clips on eBay you can get them pretty cheap.
I'll be interested to see updates on your experiments in the future. I'm sure you're right that batatas has more innate plasticity potential, are therefore likely more susceptible to graft induced variation that pandurata. That said cold hardiness is a complex characteristic so if it can be transferred might take generations of grafts. In any case, I'm sure you'll try some pollinations with pandurata pollen on these batatas graftlings relatively early on. It would be great if it could take the interspecific seed potential up from 2%.
You might be right about not needing the healing chamber, since you're working with plants with more lignin than veggie seedlings. Still even a crude humidity dome might be a good idea for a short period
Here is a second year root I just dug. Easier to harvest than I suspected even in poor soil. Dug it to 8 inches on one side then pulled it.
Interesting root, that would like growing in my soft loam soil
Yep they are interesting looking. Good to know that the big root sections tend to from right under the stem, so you wouldn't have to dig giant holes to find them.
I haven't got around to trying more grafts yet, probably do that today. I can hardly believe it but so far the one I did is still alive.
Well I cooked it up tonight. Followed the recipe online from the dewberry blog. Three total boils with two changes of water, for close to an hour. Then roasted for 30 minutes. Still had a bit of the bitter/acrid principle so I didn't eat it. I must've done something wrong because my root was younger than the one from the blog. Got to fully clear the bitterness with boiling, maybe steaming would work better.
Interesting, I didn't detect any bitterness or unpleasant taste at all in the little piece I ate raw. Like I said it was mostly tasteless. Maybe variation there?
How old was the piece you ate raw? There may be a physiological change when the plant reaches flowering age.
It would be great if it's natural variation. It has been made to taste good so maybe I didn't boil long enough.
The related Ipomoea macrorhiza can supposedly be eaten raw and has a much more diggable shape. It's hardy to at least zone 6. Leptophylla and pandurata though are hardy to 3b/4a.
Lets see, I think I started seeds in April so it was only about five months old, hadn't even been through a winter let alone get to flowering age.
Reed, thats consistent with other reports I've read, the first year roots can be eaten raw so are free of "toxicity."
Future experiments to try. Steaming the roots to see if this can more quickly clear the bitter/acrid principle. I cut the top off root to propagate with. Perhaps an older root piece can generate a new root of a decent size relatively fast. Since you're setting it back in developmental time perhaps it would have less bitterness. This cultural aspect is an important part of the influencing plants in the way we would like them to be, whether we call that domestication or not.
Quote from: Chance on 2019-10-22, 09:31:09 AM
Reed, thats consistent with other reports I've read, the first year roots can be eaten raw so are free of "toxicity."
Maybe a person could establish a permanent patch for the sole purpose of harvesting seeds and plant them every year to harvest the roots like an annual. A cross between them and batatas handled like that would be interesting. Well, I reckon a cross will be at very least interesting no matter how it turns out.
I didn't know about the toxicity issue, glad it is detectable as a taste so I don't have to worry about eating too much of it. Kind of like that awful flavor of green potato skin I reckon, one little hint of that and I spit it out.
Reed, I'm using toxicity loosely, it's probably a purgative effect as bitter components frequently are, such as other Ipomoea. I don't think it's toxic in a dangerous sense...there's a paper somewhere looking at pandurata edibility and the conclusion was something to the effect of "we don't conclusively know if it was part of native Americans diets but it doesn't appear to be dangerous"
Another thing to keep in mind regarding the grafting experiments is time. The longer you can keep the scion alive the stronger the effect will be (along with the pruning technique). This is tricky with herbaceous plants obviously because of dieback, which is why seed collection is part of the process, unlike in fruit trees where you can leave them to be transformed until you take cuttings. Batatas I guess won't die back if it's keep inside through the winter, perhaps a pandurata on batatas might stay vegetative and could be transformed over a longer period.
Interesting stuff, I take most of what I read about native Americans with a grain of salt.
The batatas scion on my first attempt finally croaked. Poor technique I think. Too much tissue of both was exposed to air instead of firmly in contact with each other.
I'v got two more now, done differently. I used small pieces of batatas root instead of stem sections, no stems or leaves at all and matched them with V shaped cuts as closely and tightly as possible using medical tape to hold them together.
Batatas roots as small as these will not ordinarily keep long, they pretty quickly start getting dry and wrinkled up. So far so good as they still look fine after a couple of weeks so any moisture or nutrients have to be coming from the pandurata root. I'm just gonna leave them as is for awhile, would about be a miracle I reckon if they started to heal together but if they do they should sprout slips next spring and I can try to pollinate with pandurata.
I used batatas roots from a couple plants I believe to be non self compatible. Figure that will make it easier to know if the pandurata pollen I bring in is working. Sure hope my other pandurata blooms next year so I don't have to drive to collect pollen.
I actually reused the same pandurata root on one of them. They must be forgiving plants cause it had sprouted new feeder roots already. Just cut it off fresh and used a V shaped edge of a cookie cutter to make the cut, reversing it on the batatas. Seems to have worked pretty good, got a nice tight fit.
My pandurata vines are now coming up for the third season. I'm noticing they're now spreading, a meter away in a couple directions. The one I harvested appears hardly effected.
Mine out at the end of the driveway along the gravel county road are doing well. Up above the weeds and growing into some wild rose bushes, very similar to the way I see them growing wild. Hoping for some flowers this year. I dug out and discarded one in the garden for fear it would take over the world. Apparently it can grow back from little bits of root left behind.
Never got around to trying the grafting again, but suppose it's not too late. I've got some super early blooming sweet potatoes this year and plenty of the pandurata.
They will come back from bits of roots, very strong too. If I could make it edible it would be a resilient food source.
My vines, even the one I harvested most of last fall, all have flower buds already. I may pick up some local sweet potato slips and try pollination this year. Probably I'll try pruning the style of batatas and putting pandurata pollen on it before going through the trouble of grafting.
Reed are you going to try any controlled crosses of pandurata to batatas this year? The 2 inch pandurata root i left in the soil last year has made a very vigorous vine.
I don't know, no good reason not too as I have batatas and pandurata flowers both available right now. The big wild one down the road has lots of blooms. I thought it had died off but noticed just yesterday, mine that I started from it's seeds also have a few flowers. I have just had lots of things going on and have kinda neglected the project.
You got organza bags? I'll send you some if you don't. Even if you just did something like 10 pollinations, half with pruning the style first, that could at least tell us something.
All righty you shamed me into it. A complication is I'm nearly positive some of my earlier flowering batatas are self pollinating. I actually kind of like that trait but makes it harder to be sure only the pandurata pollen is in play on a particular flower. I guess I have to dissect a flower before it opens?
My research on pandurata indicated that it, like batatas is also most commonly NOT self compatible. However the two plants I have collected seed from, miles apart from each other obviously are. What is your experience, thoughts on that?
I can try the cross in the other direction too now since I don't have to drive a couple miles and crawl through the weeds to the pandurata flowers.
Shame for science ;D
We know it's probably not going to work so easily but your conditions are different from the Russian researcher 100 years ago especially I would think your batatas are probably more fertile at least more diverse. Yea i guess you would have to prune the anthers before the batatas flower could self, could also bag a flower or two and see if it's self incompatible. My experience with pandurata supports self incompatibility, my first seedling that flowered alone didn't set seed until the other seedling began flowering.
So cool !
Fingers crossed in France for your pollinations to succeed!
Last time I tried this I got 2 seeds from a batatas flower that I am somewhat confident were pollinated by pandurata. They were nicely mature and well formed but they did not sprout. All the other flowers I tried it on aborted.
I'll try a larger number of flowers this time and try to be more careful in my technique.
All the earlier ones failed right away but I finally have 5 capsules developing from my (attempted) batatas x pandurata crosses. Good thing too, cause all the pandurata has about stopped blooming and I was abut to give up trying anyway.
Good luck with these capsules
Thanks, I just hope they really are crosses. I did cover them up with tea bags to keep the bees out but all but one are on the same plant and it looks like one that is probably self compatible. And I wasted quite a lot of batatas flowers in the attempt. None of the ones in the other direction worked so I won't get many seeds at all from my pandurata plants.
Interesting to see I am not the only one working in this area. I can see a lot more potential in the wider Ipomoea genus than in just trying to push batatas further. I also have macrorhiza, pandurata, a couple leptophylla (bit warm here in the subtropics for them), plus cairica. We also have abrupta and costata that are native Australian edible species, with a few others like polpha escaping my grasp so far.
Crossing batatas and other species is bound to be difficult since batatas is almost always hexaploid while most wild species are diploid. You would get tetraploids with a lopsided genome that could be awkward despite being an even copy number.
If you want to get down in the weeds there is a new monograph of the genus Ipomoea (A foundation monograph of Ipomoea
(Convolvulaceae) in the New World. John R.I. Wood1,2, Pablo Muñoz-Rodríguez1 , Bethany R.M. Williams1, Robert W. Scotland) that is a magnum opus. It does genetic analysis that helps identify closely related species, plus focuses on identifying species with edible history and useful sized roots.
My main focus with the diploids other than diploid/diploid hybridisation is to try using oryzalin to bump up the ploidy level. My main end goal is a very hardy type that can persist and size up under marginal conditions over multiple seasons to produce large roots. I am not concerned about edibility of the whole root, instead would like to develop a form that starch can be extracted from. This gets around toxins since wet milling and starch extraction allows water soluble toxins to be washed away. Just means selecting for large starch grains for easier purification.
While I think of it- does anyone know how storable Ipomoea pollen is? For individuals doing so would make wide crosses easier, plus if there are enough of us interested we may be able to swap pollen between us if it is stable when dry at room temperature.
From my other thread on turning sweet potatoes into an annual.
Quote from: Johann Kuntz on 2020-09-24, 07:02:14 PM
Regarding the discussion mid-thread about crossing I. batatas with one of the two more cold hardy diploid species:
In theory, if one of these crosses were to be successful the result would likely be (possibly) fertile tetraploids which could be further crossed and selected amongst each other, but not back to either parent species as back crossing would theoretically result in primarily sterile triploid or pentaploid progeny depending which parent was used for the back cross.
Interesting, and I hope to find out. I now have 11 good looking seeds that (I hope) are crosses between batatas and pandurata. I say I hope because I can't tell by looking, they look just like regular batatas seeds. I was careful in doing the crossing, covering the crossed flower with tea bags and all but the bees are very active on sweet potato flowers. Also I'm sure the batatas plant that made most of them is self compatible. I know it is commonly thought batatas isn't self compatible but in my plants it often is. The first seeds I ever found were from a selfed plant.
In my research I found that pandurata also isn't supposed to be self compatible but most of my seeds are collected from a single isolated plant that I found along the road a few miles away. The near 100% of seed producing flowers can't be explained by pollination from another more distant plant and their flowers are very distinct. If there was another one anywhere nearby I think I would have found it. The pollen in my attempted cross came from that plant and it's offspring now growing by my mailbox.
Now if these seeds sprout and grow next year, and if they truly are crossed it should show up as phenotype differences.
My graft attempts didn't work. I think that is probably due more to my inexperience and sloppiness than anything else.
I know a couple people at Purdue University, I may look into earlier suggestions of having them help me with germinating these seeds.
A quick search around suggest unreduced pollen is known in Ipomoea, so crossing across different ploidy levels might not be a complete waste of time.
I was refreshing the soil in my potted Ipomoea collection the last couple of days and checking out the roots. I pandurata tends to have one large central tuber with a few swollen tubers branching off in different directions. My younger I. macrorhiza have just one main tuber (often bent from hitting the bottom of the pot). I thought I crossed I. pandurata with pollen from I. cairica last year, but inspection of the tubers on the seedlings suggests they are just misidentified I. macrorhiza. The vines were twining about so I might have misidentified the species flowering, and we have plenty of bees so they might have selfed or crossed the macrorhiza onto each other without me noticing (I didn't bag any flowers, nor did I mark the flowers I hand pollinated). Hopefully I get more chances in the future to do a more careful job (I wasnt expecting anything to set first time around). I also have some I. abrupta, with much less impressive roots than the US species. I. leptophylla seems to hate my subtropical conditions and the tubers are still pea sized. I have some seed grown batatas in the mix, some with nice fat tubers, some with long irregular ones, and one strange one that had no tubers at all (is this common?). I can attach photos of the roots if anyone is interested in a particular species.
A wide range of size in the storage roots of batatas is very common. I call the ones with none at all ornamental. I've selected against that but in earlier years more than half were like that. I also have the occasional one I call clunkers were they are so big there is no way to get them out of the ground without damage and a single one would feed a family. I select against that too. I like those with a cluster of single serving sized ones directly under the main stem. I call them clump root.
What is unreduced pollen?
Interesting to hear about the variation in the batatas breeding. I will save myself the space of the one with no roots. Clunkers might be good for me since I am aiming for starch extraction rather than eating whole tubers. Slightly toxic weedy diploid species would be nice as well if I can get them a bit more productive.'
Most plants are diploid (2n) and produce haploid pollen (n) and eggs, which recombine to make a new diploid plant (back to 2n). Sometimes the total number of adult plant chromosomes doubles, triples or more to make polyploids (4n, 6n etc), who also halve their chromosome numbers when making pollen and eggs (2n and 3n respectively). If you cross a diploid (2n->n pollen) and tetraploid (4n -> 2n egg) you get a triploid (3n), with the odd chromosome number usually making them sterile (and often not even viable as an embryo). To get around this in potato you can use diploid plant pollen on tetraploid eggs, where some of the diploid pollen has failed to have its chromosomes divided in two (so still at 2n, as if it came from a tetraploid). This gives effectively diploid pollen, combined with a diploid egg to give a tetraploid embryo. That is a way of combining diploid species genetics with tetraploids in potato at least. I don't know if the same has been done in Ipomoea. The much smaller number of potential seeds per flower probably makes the odds of getting it to work a lot lower. I recall seeing such experiments done with thousands of hand pollinated flowers using diploid species pollen on batatas giving no viable seed, even with embryo rescue, but it has been a while since I went looking for such papers.