So let's say that you have a P. Lunatus x P. Polystachios. Would the P. Lunatus (first listed parent) be the female parent and the P. Polystachios (second listed) be the pollen donor? Still learning here...
That's the academic standard. Small scale breeders in home gardens don't always follow that standard. But they only switch it around 50% of the time...
Silt/clay, high-altitude, super-arid, sun-drenched, irrigated-desert garden. Cold radiant-cooled nights. ~100 frost free days. Grow most of my own locally adapted landrace seed. GDD10C ~1300. Author of Mother Earth News: Landrace Gardening Blog.
No blackox I think i've finished to retrieve all relevant paper at this stade.Next stade is to understand all the biology terms involved, cause i can't still not figure how a "steril hybrid can give rise to a fairly fertile amphidiploid"
Last Edit: Jan 26, 2014 2:57:00 GMT -5 by nicollas
am·phi·dip·loid (ăm′fĭ-dĭp′loid) adj. Having a diploid set of chromosomes derived from each parent. n. An organism or individual having a diploid set of chromosomes derived from each parent. am′phi·dip′loid·y n.
Hope it helps!
Last Edit: Jan 26, 2014 13:46:49 GMT -5 by blackox
So the sterile hybrid just has 1 chromosome from each parent (diploid, 2n=22), which they then doubled (chemicals?), resulting in the fertile amphidiploid (4n=44). Is that right? I haven't read the paper yet just guessing. Doubling the chromosome number of a sterile hybrid said to often restore fertility in the hybrid.
"...that stress, and the genome's reaction to it may underlie many formations of new species." -Barbara McClintock
Right idea, wrong n number. Most sterile cultivars are actually 3n or 5n or some other odd number of n. You usually get this by crossing a parent whose tetraploid (4n) with a normal diploid (2n). odd N numbers are sterile because the chromasomes can't pair up to divide. The doubling makes them fertile agian because the number is now even (6n 8n etc) so there are pairs again. This is also sort of what is happening in the cross. going by simple chromasome count, the cross is diploid, However because the chromasomes of each parent are so different they can line up either so it funcions as if it was 1n. The dubling provides each chromasome with a partner, and so it becomes 2n again (alibiet, a 2n in which the number "n" represents is now twice what it was for either parent.)
Suggestions are made regarding interspecific hybridization among Phaseolus species which have not been attempted, but which may be possible based on cluster analysis. These hybrids include P. vulgaris x P. polystachyus, P. vulgaris x (P. polystachyus x P. meteal/bi) and P. anisotrichos x P. angustissimus.
However, there have been no reports in the literature of attempted crosses between P. polystachyus and P. vulgaris. This would be an important hybrid to attempt. Firstly, the P. polystachyus germplasm itself is useful. Its natural habitat stretches well into the temperate latitudes of the United States, whereas all other Phaseolus species are tropical or subtropical. This species would be expected to be an excellent source of genes for cold tolerance. And secondly, if P. polystachyus did hybridize with P. vulgar- is, it could be used as a bridge between P. vulgaris and P. lunatus, and quite possibly between P. vulgaris and the P. metealfei-P, ritensis complex.
Woohooo lets try the wild x common bean cross and rule the world.
Edit : Maybe im a wrong but this could also suggest hybridation between P. polystachios and P. coccineus.
Last Edit: Feb 24, 2014 8:48:12 GMT -5 by nicollas
Cool research nicollas, looks like P. polystachios x P. coccineus is very plausible. I seem to remember seeing in a paper that P. coccineus can be found in a more bushy form in its native habitat? Looking up the species intermediary between the two, one seems interesting as well. Maybe to try interspecific crosses with P. polystachios?
It seems there are not very much pole lima beans varieties.
* Florida Butter Speckled is interesting because it seems early (68 days) * Big Mama has huge pods * Christmas has colored seeds, maybe it can be easier to see cross pollination thanks to that ?
Coming in late to this conversation, finding it very interesting. I wanted to mention re: availability of pole limas, there are lots of them. Even in the impoverished 2014 SSE yearbook, there are 90+ different pole lima varieties. Much more than the number of bush limas.
Is there any record in your literature searchs of a coccineusXpolystachios hybridization? It seems like they have a lot of characteristics in common. Perenniality, hypogeal germination, etc. One assumes that those traits are basal or potentially basal to phaseolus and would still be on homologous chromosomes. It also seems like the two species can offer a lot to each other, polystachios has cold tolerance and resistance, coccineus has huge seed size, non shattering pods, etc.
yes it seems to have more diversity that i've seen in Us nursery. I've ordered a bunch of pole lima beans from IPK genebank. For this project the most interesting are in the "potato group", that has big seeds and are perennial (and pole i guess).
I've found no mention on such a cross, but it is maybe because, as you said, they have a lot in common so there was no point to cross them (adding perenniality is the holy grail of permaculturists but not much of Big Ag). P. Polystachios has been used only to add hypogeal germination to lima beans. No point of having perenniality for the scientists (in fact Lorz used an annual lima bean for the cross).
I think it is a good idea to make an interspecific cross with runners too. But no known way to spot hybrids (maybe the way the seedling turn around the support ?).