You Can With a Yacon

It seems like another piece of received wisdom about Andean root crops must now be decapitated and left for dead in a ditch: that viable yacon seeds are hard to produce and hard to germinate. I used to subscribe to this view - until last Monday in fact. No longer. Like these newly emerging yacon seedlings, I've seen the light.

Speaking botanically, these seedlings issued forth from achenes - hard, dry fruits, looking like mini versions of black sunflower "seeds", to which they are structurally very similar. You may also see the term cypselae used to describe these non-juicy fruits. We'll let the botanists tussle over the validity of one versus the other - they're pretty much identical.

The yacon-sunflower similarity doesn't stop at the seeds - sorry - achenes. The flowers, as shown here, betray their common ancestry: both belong in the daisy family, the Asteraceae. Yacon's blooms are a shy, retiring version of the sunflower's in-your-face boldness, which seems strange, given its prodigious vegetative performance.

Anyway, I was a bit dubious about these seeds when they arrived in one of Frank van Keirsbilck's regular (and irresistible) parcels of horticultural temptation last autumn; he's the devil in disguise.... They had a certain dusty, funereal aura about them and I duly forgot all about their existence until around two weeks ago. Then, during a febrile bout of rationalisation, I rediscovered them. Grow or go, I thought as I tossed them onto some moist paper towel to imbibe.

The latter seemed more likely when they became totally covered in thick mould growth less than a week after sowing. But hold on - peering through the fungal fog, I noticed, with something akin to disbelief, that several of them were actually germinating. Result!

I claim no credit whatsoever in this success, other than the fact that I finally found the necessary motivation to actually sow them. They came from Frank's plants in Belgium and are the result of crosses between some of his varieties. Just like with oca, it appears that if you've got the right combination of varieties, seed production isn't that difficult to achieve. It will be interesting to see how they turn out, if I can get them through those awkward first few weeks of life. To the uninitiated, all seedlings look the same. We know different. Prepare to stifle those yawns when I accost you with the regulation boring baby snaps in due course.

And Now For Something Completely Different

- which has nothing to do with the Liberty Bell, John Philip Sousa or Monty Python in this instance. I mentioned previously that interspecies crosses have a useful role to play in the development of new crops.

Well, here's an illustration of what might be achieved and some of the challenges inherent in this sort of work. Not in this case a root crop - I do actually allow myself the luxury of growing a few other plants. This was a little impromptu experiment in creating a hardier squash.

Chilacayote (Cucurbita ficifolia) is by far the most vigorous and cool weather tolerant squash that will grow outdoors in Britain. As the autumn proceeds, chilacayote keeps on going, setting fruit, whereas none of the other squashes can cope with the cool wet weather that typifies our late autumns - they splutter to an undignified end months earlier. I thought it would be interesting to try and combine the exuberance and fecundity of the chilacayote with the culinary superiority of the related species C. maxima. Chilacayote also has a knife-bustingly tough shell which allows it be stored for ages - several years, in fact. That, too, would be a useful characteristic to transfer to a better quality squash.

In 2007 I pollinated a female chilacayote flower with a male C. maxima variety. To my surprise, the fruit developed and contained seeds which were intermediate between the two parental types. I planted these the following year. Several germinated and the F1 seedlings grew away vigorously, with an initial appearance somewhat like C. maxima:

I planted them out after the last frosts and they romped away.

They produced plenty of female flowers, but male flowers were rare and the anthers didn't seem to produce any pollen. I pollinated individual female flowers with pollen from either C.maxima or C. ficifolia - a process known as backcrossing. Plenty of fruits developed on the backcrossed plants, although no viable seeds seem to have been formed in any of the fruits I have examined so far.

Shame. I've still got a few left though and I daresay I'll open them up this spring, just in case. I'm tempted to blag my way into a local institute of higher education and see whether I can regenerate the plants in vitro using some of the fruit flesh, which is, of course, maternal material.

Anyway, here's the family tree laid out in the way beloved of plant breeders, with mum on the left, dad on the right and some of the interspecies offspring beneath in all their motley glory:

So that's as far as my squash breeding project has got to date. I contacted a cucurbit breeder in Slovenia, Dr Anton Ivancic, who expressed surprise that I had managed to produce any F1 seedlings at all - he normally has to excise the embryos and grow them in nutrient media before planting them out. He looked at my pictures and concluded that that there were definitely some C. maxima genes in there. His paper on Cucurbita ficifolia x maxima is here. The flesh of my fruits appears to be identical to C.ficifolia; the only difference that is obvious seems to be in the yellow skin colour.

I'm particularly fond of one of these fruits, which is large and smooth and shapely. I fondle it with a frequency that borders on the peculiar. Not so much the love that dare not speak its name as the love that doesn't yet have a name - ficifoliaphilia perhaps?

There is a link, somewhat contentious, between chilacayote and tuber crops: spermidine synthase genes derived from C.ficifolia have been used to genetically modify sweetpotatoes in Japan. The resultant transgenic plants are apparently more resistant to chilling injury and oxidative stress. They are also able to develop storage roots (the bit you eat) in lower light levels than normal sweetpotatoes. No mention of what they taste like though. So whatever your opinion on GM technology, it at least shows that C. ficifolia is a plant with some very useful attributes. Maybe if I keep crossing it with any other squashes that I happen to be growing in the patch, I might just get lucky and create a delicious new squash that climbs trees, thrives in cool weather and keeps for years. I have a dream............

Revealing My Hidden Talets

I was scratching around disconsolately in a large pot where one of my yacon varieties ought to have been. Illness and inclement weather struck at a critical moment in 2009 and now all I could find was mush. It was a beautiful sunny day, although the wind was bitter. My mood darkened as a bank of clouds headed in my direction. Seemed like a hard rain was gonna fall......

Then I remembered that a stray Amphicarpaea had appeared in that particular pot during the summer and had proceeded to climb and twine its way through the yacon foliage with abandon. It occurred to me that maybe I ought to redirect my attention towards locating any of the subterranean seeds - hog peanuts - that might be lurking amid the decay and destruction.

So I did. After a few minutes sifting through the soil, I had several of the large seeds in the palm of my hand. Not a meal's worth, I grant you, but in the world of out-there edible plants, an acceptable haul and not a single mushy one.

The thin pods (technically pericarps) were easily rubbed off to reveal the distinctive bean like markings on the seed coats. Here are the self same seeds - certainly nothing like peanuts. Underground beans is nearer the mark, hence my adoption of the name "talet", which is used in Puebla, Mexico by some of the local people who consume this plant. It means "soil bean" in the Nahua language, which is wholly appropriate I'd say.

As I've been calling them talets, I decided to cook them in the traditional Mexican way, on a hot plate. This was described in Francisco Basurto Pena's paper in the October 1999 edition of Economic Botany, the source for much of my knowledge of this plant. The toasted beans were actually rather tasty like this - I've always boiled them before.

Suffice to say that they're really quite nutritious, in a beany sort of way. Think of them as underground French beans and you won't go far wrong.

Although the yield is nothing to write home about, this is a wild plant, far from its native lands, which will survive the winter here and then grow and produce a tasty crop. There are plenty of other plants in my collection that could learn a thing or two about manners from this humble peanut that isn't.

The Root Less Travelled 1) More Peas Please - Aardaker and Caremyle

Despite my enthusiasm for root crops (and other plants) less well known, I have to accept that some minor crops are minor for a reason. Then again, I earnestly hope that, by some miracle, they can discover their own greatness. If not, I'm happy to try and thrust it upon them unbidden.

Here's a couple that, at present, fit the minor description, but are waiting in the wings to cast off the yoke of obscurity - perhaps. Like hopniss (Apios americana), they're legumes, but this time more closely related to peas than soy beans. Even more closely to sweet peas, in fact: they're both perennials in the genus Lathyrus. They fix nitrogen , as is evidenced by the large quantities of nodules attached to their roots. They have a long history as food plants and they're attractive and easy to grow (with one caveat).

These are the roots of Lathyrus tuberosus, the tuberous pea or aardaker, which is, coincidentally, the name of one of my followers, who is possibly Dutch. I grew these a couple of years ago:

Aardaker means "earth nut" in Dutch, or so I've been led to believe. The "aard" is obviously as in aardvark, so that's OK; don't know about the "aker" though. If I'm wrong, perhaps "Aardaker" would care to reveal her/himself and put me straight. Other names, in two other well-known European languages (guess which) include: macusson, tanotte and the somewhat prosaic Fyfield pea. Fyfield in Essex is the area in which the plant is most frequently naturalised in Britain. It is a pretty trailing plant with lovely bright pink flowers. It has the added bonus of producing some really delicious tubers. In my haste to get at the tubers I somehow forgot to take any pictures of the flowers at the right time. For another take on this plant, have a look at Catofstripes' experience with it.

Unfortunately the limacine reapers that infest my plot seem to find the foliage more attractive than almost anything else, producing characteristically tattered effects: Slugs one, aardaker nil:

This year's tuber, if it can be afforded that title, wasn't worthy of even the most flattering photo makeover. I'm a bit sad that I've finally run out of seeds - I rather fancied having another go this year.

What puzzles me is that we have two other members of the genus Lathyrus growing wild locally: Lathyrus sylvestris and Lathyrus linifolius. The former is a vigorous perennial that can be found trailing over the cliffs near the sea. Perhaps the extra salt deters the slugs and snails from defoliating it with the enthusiasm they show for aardaker. Maybe it's just that bit more vigorous or doesn't taste so good. It has a fibrous root system and produces quite long underground shoots, but no tubers that I'm aware of.

Lathyrus linifolius, also known as the bitter vetch is, from a root crop enthusiast's point of view, an altogether more interesting prospect. It seems to survive the depradations of molluscs with aplomb. That's a good start here at Slug Central. It has fairly upright stems, which, unlike the preceding two species, have no functional tendrils. It's a tidier plant, more suited to standard gardening practices. And guess what - it has tubers which have a long history of use as food and medicine. Like the effects of a not-so-wee deoch an dorus, this is where things start to get a bit hazy. It was, supposedly, used as a famine food in the Scottish highlands and islands, but not exactly for sustenance; consuming the tubers of caremyle (one of its Gaelic derived names) conferred upon the eater the ability to exist without hunger for weeks - it was claimed to have a powerfully suppressive effect on the appetite. Maybe it was just a practical way of dying without the added inconvenience of stomach gnawing hunger pangs.

Sounds like the ideal slimmer's food for blubbery Britons, growing, not in the Amazon rainforest or Andean Peru, but on yon bonny banks and braes. Surely someone must have done some research on this? It turns out they have. Back in 1670, Sir Robert Sibbald, one of the founders of the Edinburgh Botanic Gardens, grew it and referred to it as "Herba Scotica Miraculosa" on account of its ability to quell appetites, including his own. Just a little more recently (2005 onwards), the Agronomy Institute of Orkney College have been growing the plant, although I don't know whether they've actually harvested it yet.

In any case, the tubers, known as "knappers", were said to have a sweet, acidic taste and were dug up and dried before consuming or being added to the aforementioned dram to make a restorative tincture.

My plants cannot be said to have been high yielding so far:

Yes that really is a tuber, nestling in amongst the roots, but not a very large or appealing one. I haven't dared eat it yet. I'm still unclear whether caremyle is a one hit wonder as regards its tuber, or perhaps a mature individual produces several. My curiosity remains unsated, even if my appetite takes a nose dive when I finally get to eat it.

Apparently Nell Gwyn, that well known orange vendor and popular bedtime squeeze of Charles II, was fed caremyle tubers by the king to keep her in shape. I don't know whether this picture shows her before or after chewing her caremyle:

There are other images available, which show more of her flesh than this. Again, it's hard to draw any conclusions about the possible influence of caremyle on her body mass index. I can't quite make out whether the posy with which she coyly poses contains any caremyle, or maybe that blasted sheep ate it.

It seems to me that these two species of Lathyrus, aardaker and caremyle, have some really interesting properties. Like Batman and Robin they're a dynamic duo, with complementary qualities. But might they be even better combined? I'm talking about crossing the two species to create, ker -pow! a delicious underground confection that leaves you feeling full up for days, maybe weeks. This sort of inter-species hybridisation has a long and distinguished past in the development of new crops, witness wheat, oilseed rape, coffee, cotton and tobacco - and let's not forget dear old oca.

As far as I know, both L. tuberosus and L. linifolius have the same number of chromosomes, 2n = 14. They occur in totally different habitats, with L. linifolius found on acidic soils, whilst L. tuberosus is generally found in limestone or chalk soils. Chances are they would never meet in the wild. Matchmaker, matchmaker, make me a match. Lathyrus species don't, apparently, cross very easily, so it might get a bit technical and frustrating, involving stylar amputations, embryo rescue, polyploidisation and God knows what else. Still, I'm game for a laugh - how about you?