Got My Finger on The Pulses: The Trifoliate Triumvirate

Every year is, it seems, International Year of something or other. The cynic in me sometimes struggles with the overstimulating and diluting effect of this continual bombardment.

This year, is different, however: it's International Year of Pulses. Where would we be without beans? It seems like there's a bean or pea for everywhere, from everywhere; as readers of this blog may recall, my flexible use of the word 'root', has allowed the occasional geocarpic legume to storm the ramparts of Castle Radix in the past. No point stopping now.

My enthusiasm for talet (Amphicarpaea bracteata) is well-known and I'll come to my reasons for initiating another sowing session in due course. After some deliberation and in defiance of the impressively unpromising spring we've had, I've decided to give fate the finger and try a couple of other interesting underground legumes. So, my fellow rhizophiles, I give you my 2016 Trifoliate Triumvirate: Amphicarpaea bracteata, Arachis monticola and Vigna subterranea.

My Trifoliate Triumvirate: top left: Amphicarpaea bracteata; top right: Vigna subterranea; bottom right: Arachis monticola
Arachis monticola is probably the progenitor of the modern peanut (A. hypogaea) with which we are all familiar. The tetraploid love child of two diploid species, A. monticola, clearly a mountain lover, has appealed to me for years. It comes from the area around Jujuy in Argentina and grows at altitudes between 1300-2300 metres in the Andes. A bit of cursory research shows that A. monticola, lurking in its high mountain fastness, prefers noticeably cooler temperatures than other wild peanuts, or tolerates them at least. With a hope that never dies, my thinking is that we might be able to coax the peanut to boldy grow where it's never grown before. This chill tolerance, if true, sounds very promising, especially when its ability to cross with A. hypogaea, the cultivated peanut, is taken into account: consider the Cornish Peanut Improvement Programme duly initiated.

There's a downside, of course - this is a crop wild relative, not an actual crop, after all. The peanuts that A. monticola produces are small and the plant distributes them far and wide, so harvesting them will be a pain. That said, I expect the rodents will manage to demolish the lot with their usual aplomb.

A. monticola, diminutive monkey nuts
A. monticola, diminutive seeds
In a beautifully timed coincidence, A. ipaensis, one of the long lost parents of the peanut, has just been rediscovered. In the world of crop wild relatives, this is a big deal. The big deal in my part of the world will be whether I can get my A. monticola seeds to germinate or not and whether they'll survive our summer. Here's hoping.

If you want to know more about peanut wild relatives, including Arachis monticola, here's a good paper to start with:
Biogeography of wild Arachis (leguminosae): distribution and environmental characterisation 

For more on the fascinating sex life of the peanut and its close relatives, you could have a look at this:
Genomic relationships between the cultivated peanut (Arachis hypogaea, Leguminosae) and its close relatives revealed by double GISH

Next up, is my wild card, Bambara groundnut (Vigna subterraneana), which I chose, not for its lofty altitude of origin, chill tolerance or any other possible pre-adaptations to life in Cornwall, but because I've never grown it before and I fancied an experiment. The beans come in all sorts of colours and the  diverse batch I received looks like leguminous dolly mixture.
Vigna subterranea
Vigna subterranea is one of those intriguing African crops which has been rather eclipsed by New World invaders, in this case the peanut. It is still widely cultivated, however and has many merits, not least its resistance to high temperatures and drought, as one might expect given its origins in West Africa, probably in the hot dry parts of north eastern Nigeria. Those don't sound much like the climatic challenges we usually face here in Cornwall, but no less an authority than William Woys Weaver claims that there's a basic rule of thumb: if you can grow outdoor tomatoes, you can grow Vigna subterranea. Given the spectacular levels of Phytophthora infestans on our plot, which carries off our outdoor tomatoes and potatoes every year, this is but little comfort. He's referring to temperature, of course, rather than pathogen load; the way I see it, nothing ventured, nothing gained.  And you never know, a cold spring does not guarantee an indifferent summer. It might even encourage me to finally read this:

The mature beans are eaten roasted or boiled and are considered a complete food, containing about 65% carbohydrate, 18%  balanced protein and 6.5% fat; bambara groundnut milk is said to be more palatable than soya milk, which can only be a good thing. In terms of bean distribution, it looks like the plants have abandoned their wild child ancestral habits and deposit their pods demurely, close to the base of the plants. For that the voles will be duly grateful.

Last but no means least, I give you talet (Amphicarpaea bracteata), tried and tested in our climate. Following on from the success of that trial, I was heartbroken when, a few weeks later, a pheasant plucker emptied the pots, scattered the labels and pretty much gobbled the entire crop, eliminating several varieties in the process. Not so fast, Mr Pheasant! All is not lost, due to talet's cunning amphicarpic strategy, whereby it hedges its bets through the production of different types of seeds, including hard, long-lived ones. I've kept a stash of the latter type of all my varieties in case of just such an eventuality. Time to open it and resurrect those that were lost. I'll give the finger to a pheasant just as soon as I will to fate.
Sprouting subterranean talets (Amphicarpaea bracteata)
My talet resurrection enthusiasm knows no bounds. I've been inspired to open the dusty Radix crypt and disinter some seeds of varieties I placed there at the end of last century, when I first started tinkering with the plant in earnest. Are they still viable, after nearly twenty years?  If I have the time, I'd also like to get my head around the latest research which identifies three cryptic species within Amphicarpaea bracteata sensu lato and try and see which ones I've got. Help! Can I possibly cope with yet another trifoliate triumvirate?


orflo said…
Good luck with your arachis seeds! I tried vigna subterranea for two years, and the plants didn't develop wel, even not in the greenhouse. Most of the plants died when they were about 10-15 cms high, the one that survived didn't grow any more and not a single nut was produced. Maybe I just had the wrong variety? Or something else was wrong, I don't know..?
Brent said…
Your Bambara groundnut seeds have a much higher variation than the ones I have seen. All of mine are uniform in size and light tan in color. Interested to see how they do.
Rhizowen said…
Thanks Frank

It seems like it might be a challenging season, even for a high altitude peanut. We'll see. As for the Vigna, I will be very surprised if it succeeds, but nothing ventured, nothing gained.

Rhizowen said…
They do seem to be mixed bunch, Brent, so perhaps that will help. One can but try.