I am currently starting work on other species of Ipomoea that have some history of use for edible tubers (though preparation is normally more involved than for sweet potato). I currently have I. cairica growing wild in my paddocks, along with I. abrupta (an Australian subtropical native, unflowered but apparently needs to climb to induce budding), I. costata (a desert native, which started out OK but has since died off, unflowered), I. pandurata (flowering well second year, nice looking roots), I. macrorhiza (first year, unflowered, but growing well), and a couple I leptophylla (very small and not terribly happy after two years). I am also trying to track down the native I. polpha (which is likely to be a pain to grow) and I. calobra (grown on a small scale commercially on the other end of the continent) and a couple of other species from overseas. There is another small edible species from my area I am tracking down but I forget the name. I. lacunosa looks interesting but maybe too weedy to handle well.
This is all very preliminary and speculative work, but I have already had some apparent success crossing I. cairica pollen onto a potted I. pandurata. The seeds were a little distorted, as were the cotyledons and now the true leaves. Roots are swelling nicely. An Ipomoea expert thought they looked like macrorhiza but I was pretty sure I identified the seed parent properly (though a nearby macrorhiza might have reached across and gotten tangled up in the pandurata). How likely is self pollination in the seed parent? I only noticed seeds being formed where I managed to hand pollinate, with the other spots I missed dropping off almost immediately.
Is anyone else in this group interested in other species of Ipomoea? I might do some crossing of species with batatas but the diploid/tetraploid gap might be a problem.
