Monday, 24 May 2010

Oh Heck, Here's Mecha-meck

In my quest to create the perfect sweetpotato for our unsympathetic climate, I've been doing a bit of hunting around for some of its wild relatives. This is an approach used by proper plant breeders to introduce genes for disease resistance and adaptability into major crops. I'm not sure whether this means that I'm now dragging myself up to their level, or whether the plant breeding brethren (and sistren) will be tainted by association with my madcap antics. If you don't tell, I won't either.

Mecha-meck or bigroot morning glory (Ipomoea pandurata) is one of the most cold tolerant sweetpotato relatives, being found in parts of the Eastern USA and Canada which have much colder winters than we do here in the UK. Its roots are edible and taste, unsurprisingly, like a sweetpotato, although several references mention that they are often somewhat bitter. Although said roots can survive sub-zero temperatures with ease, it doesn't mean that the vines that issue from them are going to like our cloudy, cool summers. It's what I call the Maypop Paradox, after the "hardy" passionflower Passiflora incarnata. It comes from the same neck of the woods as mecha-meck and although it can easily survive our laughably mild winters in a dormant state, our summers (or lack thereof) are fatal to it. At least whenever I try and grow it. I'm reminded of Mark Twain's supposed quip about the coldest winter he ever spent being a summer in San Francisco. He should have visited Cornwall. Anyway, my guess is that mecha-meck is cast in the same mould and at best its vigour will be severely checked by that lack of summer warmth. Time will tell.

It does, however, have a close relative, Ipomoea leptophylla, which grows out in the western USA at quite high altitudes, up to 2000 metres or so in Colorado, for instance. It has been described variously as delicious, or as a famine food - take your pick. One of I. leptophylla's vernacular names is "manroot" - I suggest caution when Googling that name and make no claims expressed or implied as to what sort of images or text may storm your computer as a result.

Rather than a vine, I. leptophylla is distinctly bushy, which might make it easier to manage as a garden plant. It might take cooler summer temperatures in its stride. That set me thinking about how it might be fun to have a go at crossing the two species and seeing what comes out. That's a lot of mights for one paragraph, but three mights don't make me wrong do they?

These are the seeds of mecha-meck, looking like shaggy understudies for Cousin Itt from The Addams Family. I'm not sure what the purpose of the coiffure is - the seeds are about 1cm long - quite substantial - and I can't imagine that even this amount of fluff would carry them very far on the breeze.

Here are some mecha-meck seedlings with the distinctive delta wing cotyledons which all the Ipomoea species I've ever grown seem to display.

Sweetpotato is a hexaploid with six sets of each chromosome (2n = 6x = 90) whereas mecha-meck and manroot are both diploid (2n = 30); most of the literature suggests that interspecies crosses between sweetpotato and its wild relatives are hard to achieve anyway - never mind the differences in ploidy - which isn't really what I wanted to hear. However, last year's impossibility is this year's commonplace: I recently came across a paper by some Chinese researchers where they had managed to do exactly this. The abstract is here. The actual paper lurks behind a paywall, thumbing its nose, no doubt, at us mere mortals who don't fancy spending $34 on the full text.

This idea of using I. pandurata to increase the cold hardiness of sweetpotato is nothing new - I'm merely ram-raiding the vaults of yesteryear and grabbing whatever takes my fancy. In a 1935 paper in the Journal of Heredity, M G Tioutine outlines his work on breeding sweetpotatoes in the USSR and goes on to describe his attempts at crossing I. batatas with I. pandurata. A few pods were formed, but there's no mention of whether they contained viable seeds or not. I haven't found any other papers referring to his further research on this front either. Judging by the fate of Vavilov, working as a plant breeder and geneticist at this time was not, perhaps, the safest career path in Soviet science. (There's more on Vavilov at Vaviblog - a great, great man).

Tovarishch Tioutine does, however, describe the roots of I. pandurata as tasting similar to Jerusalem artichokes, which doesn't sound so bad after all. Perhaps it's just a case of harvesting them young, before they become tainted with whatever it is that makes them bitter.

So all I need to do now is get hold of some I. leptophylla seeds, grow the plants to maturity, then set up an Ipomoea menage a trois with I. pandurata and the best adapted I. batatas varieties, including ones from the highest sweepotato plots in the Highlands of Papua New Guinea.

Should be an absolute breeze. In the meantime, I'm waiting on the universe to deliver me seeds of yet another Ipomoea: the fabled sweet-tasting, high altitude Andean species I. minuta. I'll throw that into the mix when it finally arrives. I don't know what the collective noun for a disparate bunch of ipomoeas is - could it be an entanglement? What I do know is that I'd like the chromosomes of this motley crew of morning glories to commingle and maybe create something interesting in subsequent generations. You say potato, but I say batatas - and I won't call the whole thing off.

Wednesday, 19 May 2010

Yabadabadoo - Yabumame's Poking Through!

This is the emerging shoot of yabumame (Amhicarpaea edgeworthii), whose Japanese name translates as something like bush soy. The more typical trifoliate leaves will follow shortly. It looks very similar to Amphicarpaea bracteata, talet or hog peanut, about which I have been known to hold forth for hours on end to interested parties. They were the ones who didn't nod off, or stare out the window at some particularly fascinating cloud formations. But seriously, just like talet, this is a tasty plant, with the same sort of potential.

It is sometimes classified as Amphicarapa bracteata subsp. edgeworthii var japonica, which suggests that the resemblance to talet is more than superficial. Unlike its New World cousin, it has been subjected to some scrutiny as a potential food crop by the Japanese. If you fancy practicing your hiragana, katakana and kanji comprehension, then here's a good place to start. I tend to skip over the text and look at the pretty pictures. Nevertheless, it's probably a safe bet that these research findings would be applicable to talet as well. Scroll to the bottom for the English abstract. For other hard core Amphicarpaea edgeworthii fans there's more where that one came from. Or maybe I'm the only one.

One of the advantages of the amphicarpic habit is that the plant produces two types of seeds, the cleistogamous, self pollinated ones (underground and overground, just like the Wombles) and the open pollinated chasmogamous seeds from the flowers at the top of the plant. It should be possible to allow or assist the plants in crossing using the chasmogamous route, then sow the resulting seeds and maintain any favourable ones via the seeds produced by the handily self-fertilising cleistogamous flowers. That's my theoretical take on it anyway, which I've had no opportunity to verify or disprove so far.

I'm also wondering whether the two species can be crossed to introduce a bit of extra genetic variation. I haven't tried it and don't know whether it's possible, but seeing as the two are so closely related, it must be an avenue worth exploring.

As to differences, well, A. bracteata and A. edgeworthii are known to be colonised by different varieties of rhizobial bacteria, with A. edgeworthii unable to use the strains found on A. bracteata; A. bracteata, however, can use A. edgeworthii's bacteria. I shall have to see whether any nodules form on my yabumame's roots later on. Not much point having a plant with the ability to fix nitrogen without providing it with the means to do so.

Then there's A. africana - yes, an African hog peanut about which I know precious little, other than that it grows in montane Africa at elevations of around 2000 metres or so. For the sake of completeness, I really ought to try and grow it.

Delving deep into the Gormenghastian recesses of the internet in search of all this stuff is fun, but can't quite compete with the pleasure of devouring a plate of cooked talets, steaming majestically and crowned with a knob of butter. The former I can do any day; the latter, regrettably, will have to wait until the autumn.

Thursday, 13 May 2010

Yond Yacons Have a Lean and Hungry Look

Shakespeare, with his impressive knowledge of plants and their uses, might have looked on my yacon seedlings and said the above. I'm guessing that yacon hadn't made it to London by the 1590s or Stratford's finest scribbler would have mentioned it: "Why man, it doth bestride the narrow border like a colossus and we petty men walk under its huge branches and peep about.... Let me have about me roots that are fat". You get the drift.

Fast forward a few centuries, stepping nimbly from doublet and hose into a zoot suit and let the good times roll with Louis Jordan. "Long, lean and lanky, ain't had nothing to eat" is his description of the eponymous protagonist in the 1945 hit Caldonia. That would apply equally well to my yacons. I've been waiting for the weather to warm up and lacking the necessary space to pot them on, they've got distinctly malnourished. Ain't that the truth! Well Louis, they're my babies and I love 'em just the same. I'm hoping that as soon as they get into the ground, they'll forgive me.

Wednesday, 5 May 2010

Getting Arty and Chic with Helianthus

Here's a brand new way to eat your Jerusalem artichokes: blanched - the shoots, that is. I call them artichicons. If it works for rhubarb, sea kale, chicory and a host of other plants, why not that irrepressible artichoke impostor Helianthus tuberosus? Lest you think me smug, I had absolutely no intention of doing any of this. Call it serendipity, call it fortuitous, but as far as I'm concerned, it was an accident.

An errant patch of rampant Jerusalem artichokes needed eliminating. I couldn't face digging them up, so the answer seemed simple: I'd cover them with light-excluding weed control fabric and hope the buggers died off before the bed was needed. I'd reckoned without girasole mio's thrusting and aggressive growth, however.

Weeks passed, then the fabric began to rise like a bloated loaf. Intrigued by this Greater Black-Backed Multiple Tumescence, I pulled the cover away to reveal a forest of pallid artichoke shoots. I picked one and chewed on it for a moment. Not bad, I thought. Not bad at all. I harvested the rest and later that day, I cooked them.

Although ginger, garlic, soy sauce and chillies can make most things palatable, these artichicons really were rather tasty. No doubt correct varietal selection and time of harvesting would lead to an even better experience, reducing the chew factor, but for a first (and unexpected) attempt, I was quite pleasantly surprised. More research is therefore needed, but all in all, a topping way to eat your topinambours. No more will I look upon redundant artichoke capacity with a sinking heart - I'll fire up the wok instead.

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