A different approach to sweet potato breeding

[walt]

Gilbert
I run the annual seed sale for the Species Iris Group of North America, so I have an import permit for the whole iris family.  It is free online, and while it took an hour or so to fill out forms, it is free.  It is emailed to you.
I often get bags with 100 or more seeds of a variety, and several varieties per shipment..  Never been a problem.
We do have to not import things from the noxious plant list, like Iris pseudacorus, or endangered species.  But the permit is good for 3 years, and you can add species or genera or families.  The only limitation is that it be something that it is legal to have and import.

[reed]

billw, concerning the statement you made earlier in the thread "then it likely has some sort of incompatibility defeating mutation"



Could you elaborate any more on that? Would it be heritable? Stable? Subject to being dominant or recessive? The first I batatas I ever got seed from had it.

Selfed descendants of that plant bloomed massively but made almost no seeds at all, even with plenty of other varieties nearby. 

One of the crossed descendants of that plant definitely has it and I'm pretty sure at least one more also does. 

Assuming the specimen of I pandurata also has it, is it likely it's selfed dependents will also not? I need to cross it to another I pondurata specimen to propagate the trait? 

Will it be of use it in efforts to cross the two species?  

 Research I found on i pandurata said they were kind of stumped on the wide spread distribution given the self incompatibility but one in seven isn't all that rare.  Since I have stumbled on specimens of both species that have it, is it possible that it isn't a random and rare mutation but rather a gene combination that really isn't that rare at all?

gilbert, I apologize again for intruding on your non-sweet potato, sweet potato thread. I can only offer some seeds from the first ever I batadurada as consolation.   In the unlikely case it ever happens. 

[billw]

I really don't know that much about sweet potato. It doesn't yield anything here, so I haven't really worked with it other than to evaluate some varieties to see if if they would tolerate our low summer temps. Sweet potato has sporophytic self-incompatibility. In that system, any variety that has at least one matching S allele is incompatible. So self-incompatibility is supposed to be absolute and cross-compatibility is also often very limited in local populations. Polyploidy breaks self-incompatibility, but in less predictable ways with SSI than GSI - in fact, I don't think that the method by which it breaks SSI is understood yet. (Theoretically, cross-compatibility should be reduced in SSI polyploids, since they would have a larger number of S alleles and thus a larger number of incompatible matches in the population, but it doesn't actually turn out this way.)

If you have a variety that is diploid and self-compatible, then it must have a mutation that overrides the SI. Such mutations exist in some plants. For example, S. chacoense has an S locus inhibitor gene that breaks self-incompatibility in diploid potatoes. In that case, it is heritable and dominant, but there is no reason to expect that would always be the case. If a variety is polyploid and self-compatible, then it could just be the result of polyploid breakage of the SI system. While GSI polyploids tend to become fully self-compatible, SSI polyploids still tend to be mostly incompatible.

I don't think much work has been done with I. pandurata. It could be that many of them are self-compatible or it could be that you just stumbled across a rare one (or, that it has been pollinated by a plant that you didn't notice, although the seed set that you described sounds characteristic of a self-compatible plant.) It is impossible to guess the genetics. Since I. pandurata is (always?) diploid, self compatibility would have probably arisen as a mutation. It would likely be dominant, since it would be difficult to get a cross that would yield a homozygous recessive with an intact self-incompatibility mechanism. Of course, this could turn out to be a polyploid S. pandurata, in which case all bets are off. In polyploids, unusual features are often dosage related and therefore difficult to track. A trait that only expresses when it is quadriplex or hexaplex recessive might be very rare in a population and nearly impossible to preserve in a cross.

[gilbert]

Post by walt on 6 hours ago
Gilbert
I run the annual seed sale for the Species Iris Group of North America, so I have an import permit for the whole iris family. It is free online, and while it took an hour or so to fill out forms, it is free. It is emailed to you.
I often get bags with 100 or more seeds of a variety, and several varieties per shipment.. Never been a problem.
We do have to not import things from the noxious plant list, like Iris pseudacorus, or endangered species. But the permit is good for 3 years, and you can add species or genera or families. The only limitation is that it be something that it is legal to have and import.

Thanks Walt, that is helpful

billw, concerning the statement you made earlier in the thread "then it likely has some sort of incompatibility defeating mutation" gilbert, I apologize again for intruding on your non-sweet potato, sweet potato thread. I can only offer some seeds from the first ever I batadurada as consolation. In the unlikely case it ever happens.

No problem, I'm interested in this too. I'd think self incompatibility would be better, it helps to make crosses; Joseph is working on making his outbreeding tomatoes self incompatible. 

[gilbert]

Hi Walt,

On the USDA website they state the following about a small seed lot permit; do you find this to be not the case, or do you have a different sort of permit? 

(i) A typed or legibly printed seed list/invoice accompanies each shipment with the name of the collector/shipper, the botanical names (at least to genus, preferably to species level) listed alphabetically, as well as the country of origin, and country shipped from, for each taxon. Each seed packet is clearly labeled with the name of the collector/shipper, the country of origin, and the scientific name at least to the genus, and preferably to the species, level. The invoice/seed list may provide a code for each lot, which may be used on the seed packets in lieu of the full list of required information. In this case, each packet must at least include the appropriate code, which is referenced to the entry for that packet on the seed list/invoice.
(ii) There are a maximum of 50 seeds of 1 taxon (taxonomic category such as genus, species, cultivar, etc.) per packet; or a maximum weight not to exceed 10 grams of seed of 1 taxon per packet;
(iii) There are a maximum of 50 seed packets per shipment;
(iv) The seeds are free from pesticides;
(v) The seeds are securely packaged in packets or envelopes and sealed to prevent spillage [Note: we recommend that seeds are packed in resealable, clear plastic envelopes to facilitate inspection];
(vi) The shipment is free from soil, plant material other than seed, other foreign matter or debris, seeds in the fruit or seed pod, and living organisms such as parasitic plants, pathogens, insects, snails, mites; and
(vii) At the time of importation, the shipment is sent to an approved port of entry listed in the permit.

[Joseph Lofthouse]

It seemed to me, when I broke self-incompatibility by crossing domestic tomatoes to Solanum habrochaites, that self-incompatibility was restored in some of the G2 plants. I'm estimating, based on not-carefully measured observation, that self-incompatibility was restored in about 10% of the plants. (Two genes involved in restoration?)

[reed]

I feel like self compatibility in a species most commonly otherwise might have value somehow. I don't really know how. Maybe it can help open up other non-seed producing varieties to produce seeds. Mostly I just like getting lots of seeds instead of a few or none.

[reed]

Found this article about the origin(s) of I batatas. Most of it is well above my pay grade but it may be of interest in this project. journals.plos.org/plosone/article?id=10.1371/journal.pone.0062707 

[gilbert]

I just received seeds for Ipomoea lacunosa and I. leptophylla today. Still trying to figure out how to get a hold of seeds of I. costata.

[gilbert]

I've run into a problem; I can't seem to get seeds for Ipomoea costata, at least not without spending hundreds of dollars. The attraction of this particular variety is that it is a diploid with good quality tubers, unlike most of the American diploids, which have survival food quality tubers.

Does anyone know of other diploid Ipomoea species that have decent tuber quality? I don't care whether they are tropical or temperate, or about any other qualities.