Crap Crops of the Incas: my on-off-on affair with Andean root crops 4) Pachyrhizus - ahipa useless junk?

"Four legs legs good, two legs better!"  That was the bleat of the  sheep in George Orwell's 1945  allegorical tale  Animal Farm.  Their masters, the ruthless and conniving pigs, had just started strutting about on two legs and were all set to take over where the banished humans had left off. 

So, you may well ask, what the hell is the relevance of this to root crops? George Orwell's interest in roots and tubers seems to have been limited to an oblique reference to potatoes in The Road to Wigan Pier and mangelwurzels, which get a mention in Animal Farm.  No, I'm not suffering from a mashua overdose;  hopefully we all know by now that root crops are good nutritious fare and we could certainly grow a greater diversity of them.  But nitrogen fixing root crops, ones that gather nitrogen from the air and deposit it at their roots, must be even better: fill your stomach and feed your soil at the same time.  These are the Holy Grail of the rootcroppin-nostoppin-tubertastin-timewastin-globescourin-cataloguedevourin-seedbuyin-diversifyin permie (who may or may not drink any of a number of noxious carbonated beverages). 

There are a few  possible  contenders for our cool temperate climate, such as Lathyrus tuberosusPsoralea esculenta  and Apios americana - I'll attempt to cover these in later posts - and a whole load more if you move into warmer zones. Seeing as we enjoy a cool moist climate here in Britain and complain like hell about it, I think I'll limit my researches to the moan zone with which I am most familiar. 

Pachyrhizus is a genus of tuber forming beans, sometimes known as yam beans. There are several species.  The most familiar, perhaps, is jicama, Pachyrhizus erosus from Mexico and Guatemala , the roots of which are  sometimes sold in exotic markets, or you may see the seeds offered by specialist seed companies.  The 
other main species is Pachyrhizus tuberosus, probably a native of Amazonian Peru.
As you might easily deduce from their places of origin, these two Pachyrhizus species like much warmer summers than we have here, as do a considerable proportion of the populace, who apparently now live in Spain.  In fact, I daresay jicama would grow quite well there. There is, however, a higher altitude species, ahipa, Pachyrhizus ahipa, found in  Bolivia at around the same sort of elevations as yacon grows.  Not only is it better adapted to cooler climates than the other species, it is also day neutral, which jicama, for example, is not. Hallelujah, so far, so good.  It's also, usually, a bushy, free standing plant without the exuberant twining growth of its fellow species.   Brilliant.   But before we open a bottle and celebrate the advent of a new crop, one the good old boys down the allotment will roll their eyes skyward over,  how cool is cooler?  Oh yeah and what does it taste like?                                                                   
I grew my first plants back in the early 90s from seeds that were supplied by the Yam Bean Project in Denmark, led by Marten Sorensen.  Unfortunately it doesn't seem to exist any more - correct me if I'm wrong Marten.   There were initial problems with some of the ahipa seeds which had been grown in Tonga and were DOA.    Still, the hardened root crop obsessive knows that there are many twists and turns on the steep and rugged pathway to the sunlit uplands where fields of comingling  tubers flourish in delicious, delightful abundance.   The next lot of seed I received produced a few plants which were planted out in a polytunnel.   They had, unsurprisingly, bean like foliage and looked reasonably happy.  

They bore attractive purple flowers and produced large pods.  Then the cold weather came and I decided to move them somewhere warmer.  The roots were small affairs, (the vernacular"piddling" springs to mind), but I shrugged my shoulders and thought about those sunlit fields again. 

It turns out that the flowers are usually removed as a traditional husbandry technique to increase the root size. This makes perfect sense if you think about it - the developing seeds are bound to draw resources away from the bit we're after: the tubers.  So reproductive pruning is necessary, although it does present a few difficulties from a breeding point of view, especially  as ahipa is usually grown from seed every year.  

Time passes. Listen. Time passes.   Ahipa fades out of my life and then, inveigles its way back in, all over the space of a decade or so. May 2005: I find myself once again planting a few young ahipa seedlings into the ground, hoping that neither frost nor slugs will stop me from getting to try the sweet and juicy flesh of the Andean yam bean.

The plants grow well and seem to enjoy the warm summer.  I decide that rather than sacrificing the plants, I really ought to build up my seed stocks, so I forgo the delights of reproductive pruning and let the pods develop.  

The intimate study of drying paint seems almost unbearably exciting when compared to waiting for ahipa pods to ripen.  It all starts quite nicely with the purple flowers which seem to set easily and produce little bean pods - so far, so good. They swell quite rapidly and appear full of promise.  The pods get longer and fatter, with buxom bulges around each seed.   This is looking good.  Then the long wait begins.  Maybe it's just our wan late summer sun that fails to get them going, I don't know.   Those pods just sit there in a state of suspended animation like killjoy Walt Disneys.  Then, as the season deteriorates, the slugs seem to realise that rotenone, the insecticidal compound contained in the seeds, presents no threat to them;  to prove the point they tunnel their way through with their customary bare faced cheek.  Yes, slugs do have faces.  I just wish they'd keep their rasping tongues off my plants. 

Disgusted by the rank ingratitude the plants showed, a red mist descended and I decided to abandon them.  I sent the seeds of my two varieties to Frank van Keirsbilck, worthy contender to the as-yet-uncreated title of Mr More Agrobiodiversity per Square  Metre than Anyone Else (Europe).   As I suspected, he is a better grower than me - he has even been offering seeds through Seed Savers Exchange this year.   Another source, if you're still interested, is AndeanCrop Seeds on eBay.  

I recanted, of course and grew ahipa last year in a desultory way: two stunted plants in pots.   Here's proof, if any were needed, of why I should not be let loose on unsuspecting Andean root crops:

Never was the phrase "small, but perfectly formed" more apposite.  I took the offending plant, peeled the tuber and ate it.  It was sweet, certainly, but with a slightly starchy taste and texture like that of a raw potato, not that I eat raw potatoes that often, only as part of a calorie-controlled diet.  Still, it wasn't bad and would probably have been a lot better in a bigger pot where the tuber could have developed properly. 

Ahipa can grow grow quite well in the British climate, but I would say a good summer is needed.  2007 and 2008 were not vintage years for ahipa in the UK. 

To guarantee success they'll  need to be started off in a greenhouse and if you want ripe seeds, a greenhouse, polytunnel or cloche will ensure they get the extra heat needed to ripen those seeds.   Eduardo Leidi Montes, an ahipa researcher in Spain told me that he thinks the crop has real possibilities in a Mediterranean climate. Such summers tend to be the exception rather than the rule here. All those ex-pat Brits, downing Newcastle Brown and chewing  Marmite sandwiches - they
may be missing out on the ahipa plants growing in the fields opposite El Pub.  

So the school report might read something along these lines : "Ahipa shows promise, with the potential to make a useful and original  contribution. However, Ahipa  must concentrate on completing tasks in a satisfactory manner within agreed time frames and show adaptability in dealing with changing circumstances".  Overall score C-. 


threnody said…
Hmm, yours sort of resembles a turnip - but I take it you spent a lot more time and energy to get that then most turnip growers would. I'm about to start experimenting with oca and yacon in upcountry Hawaii, and I hope I have better luck than you.
Ottawa Gardener said…
Well now I'm thoroughly blase about growing this plant now but much better informed about some of the challenges of growing them in the UK. As I live in Canada, I read this with a certain sense of exotica and then wonder if the variety that I saw growing at Solana Seeds(?) is worth a try? Though it is not the bushy one I think.