I posted a blog post a while ago about learning to hand cross sword beans.
I had grown C. gladiata for years, impressed by its vigor but never got around to figuring out how to detoxify the dry beans. Then I lucked onto getting C. ensiformis (a more domesticated species IMO) and C. papuana (a pretty much wild form). I decided to grow them all together and hand cross them. My ultimate aim is a dry staple legume that I can plant in my orchard and hedge rows and do nothing more than harvest the pods at the end of the season. C. gladiata is close to this, but injecting some more diversity should help me refine it.
With winter here the mature seeds from the hand crossing are coming in and I noticed something interesting. This is a follow up to the other thread asking if it is possible to distinguish first generation hybrid seed from self pollinated in P. vulgaris. I am pretty sure I am seeing differences in my C. papuana seed at least. The original C. papuana seed was jet black, with such a thick seed coat it needed to be sanded back to induce reliable germination.
Unfortunately my trellises collapsed in a storm, and some of the tags on the hand crossed spikes fell off. That meant I only had a few spikes marked that were definite hybrids (I will use a better label technique next time). The hybrid seeds looked different to the pure species- kind of blotchy khaki, unlike the solid black original pure species.
The remainder of the papuana seed was a mix of OP (and possibly pure/self pollinated) and some hand crossed pods where the labels fell off. I sorted them by colour to make the two kinds more obvious:
I’m only planning to grow out the definite hybridised seed next season to assess their traits, plus some pure C. gladiata to back cross since I am estimating something with around 75% of its genetics will be my ideal. Ideally it would be fun to sow the black and khaki seeds separately to find out if the colour does indeed indicate hybridisation. If anyone wants to give this a try let me know and I will share the seed for the cost of postage (though there is a risk they might get seized before they can leave Australia thanks to our ever more paranoid quarantine service).
Sword beans have been on my radar for a while - - I think they may have made @Lowell_McCampbell’s list as well if he’s not already growing them. There’s a breeding project at the EFN that may still be ongoing for evaluating their use as companion crops to young trees.
I would be interested on trying to grow a small amount this season if that seems feasible in zone 6 - - a lot of my remaining climbing bean space will probably go to limas from friends.
My guess is I’m not the only one in the states who’s interested
I’d be curious to know how far from the equator they can grow. C. ensiformis was the fastest to mature for me. Being stuck in Australia means I can only (sometimes) export large seeds like this. Importing new varieties into the country is almost impossible for amateur breeders (hence why I only took on the project when I got lucky with three different species). Pollen might open possibilities though, if it can stay viable for long enough after postage.
How active is the EFN these days? I started a Canna group project but could never get the messaging/email system working so it kind of died without going anywhere despite a few people signing up. I did manage to work around it and send seed from my crossing program to a few US growers independently and they seem to be doing well with it. My strain seems to be unusually freeze resistant, which is something I could never have selected for.
Colour variation is pretty common in Phaseolus vulgaris but I don’t know about the genus Canavalia. I’m pretty sure though that the pericarp is maternal tissue so can’t be affected in the F1. Sounds like you have known hybrids anyway. Should be fun growing them out.
The parent species seed colours are bright pink for gladiata, white for ensiformis and jet black for pure papuana. That was why the appearance of khaki coloured seed in the hybrid papuana was noteworthy. The seed that I was certain as being from hybridisation was pretty uniformly khaki in colour. Changes in the hybrid endocarp of the seed might possibly bleed over into visible traits from the outside. No sign of any visible variations in the seeds of the other two species when hybridised.
I wonder if exosomes or some other factor ever travels from the embryo to the seed coat. Could account for observations of visible changes in the seed coats of hybrid legume seeds from others.
Even if exosomes remain bound to the cell membrane, being extracellular means their contents could find their way to the ‘outside’ and affect seed coat colour. It’s all so complex anything is possible.
Would you backcross the hybrids? Wide crosses can sometimes be self-infertile but will accept pollen from a parent, but I guess you’re aware of this, given your extensive knowledge (evidenced by your posts).
I’m not 100% sure what the next step with the F1 sword bean grow out will be. I will probably pool pollen from all of the F1 hybrids and back cross onto pure gladiata. I love doing pooled pollen crosses since your chance of getting something for your efforts goes way up. At the most I might separate out pooled pollen from multiple gladiatax, ensiformisx and papuanax populations. Any more than three kinds of crosses and the organisation gets annoying. That way there should be plenty of F1 flowers I can leave to self pollinate as well. That highly mixed population F2 self pollinated (or maybe the odd bee crossed) population will be the ideal thing to share with others. The hand crossed back cross though will be less abundant, so I might need a bit more coaxing to share seed depending on how much I get. I could also be brave and plant the F2 self pollinated seed all over my orchard and hedge rows to screen for vigor without any assistance.
I would happily do my part try to find out. Anecdotally, some red sword bean seems to grow wherever Longmeimei is. But I don’t know how far from the equator she is - - honestly the only reason I know who she is is from watching that sword bean video last year.
I’m not currently participating in any of their projects so I’m not sure. I think it varies by breeding project.
It looks like there are a number of still active projects. Haven’t noticed a new project added since the cold hardy avocado project though
Id love to send anyone seed (happy to do so for the cost of postage). Unfortunately Australian authorities have started seizing seed on its way out of the country (previously they only bothered with stuff coming in). So it might disappear on the way, but happy to try if you are willing to risk wasting your money on some postage.
