Author Topic: Ipomoea pandurata, aka man root, man of the earth, wild sweet potato  (Read 2109 times)

reed

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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?

S.Simonsen

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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.