Sunday, 30 August 2009

A Flurry of Flowers

It's now over a month since the first flowers appeared on one of my oca seedlings - RX0916, to be precise. The weather has been against us (that's me and the ocas), but has now improved to the point at which wan sunlight filters through leaden skies on occasion and allows me to see my own hand at arm's length. Poetic licence, maybe, but cloud cover has been unusually dense over the last two months and the rainfall exceptionally high. We've just been slapped by the dying gasps of Hurricane Bill as the final hurrah to a supremely indifferent August. There's a distinct autumnal chill in the air these mornings; this is all very well, but it would have been nice to have had a bit more of the azure skies and blazing sunshine that we associate with summer before slipping inexorably into the no man's land of November and beyond.

No matter - an increasing number of the other oca seedlings are starting to flower, so I've decided to try and ascertain what kind of stylar arrangement each individual has. This should make it a little easier to cross pollinate them and produce more botanical seed, ready for a further round of sowing, growing and selecting.

As of yesterday there are 15 seedlings in flower, with another four likely to do so in a few days.

Of the flowers I have examined so far, two stylar morphs are present. Consulting my CIP oca descriptors I find these are 1) brevistilia and 2) mesostilia - that's short-styled and medium-styled. I haven't seen any long-styled flowers yet, although I'm pretty sure that some of the potential parents in my possession display this trait. The following image will hopefully make apparent the differences.

The flower on the left has the stigmas positioned at the base of the flower, below both whorls of stamens and is thus short-styled. The flower on the right has the stigmas between the whorls of stamens and is therefore mid-styled.

Breathless update: I've now discovered a seedling (0905 to be precise),with the third type of flower, called in CIP lingo "longostilia", or long-styled. I didn't have my camera with me, unfortunately.

So far the short styles outnumber the medium styles by roughly 2:1, which seems strangely significant and will no doubt prompt me to go and do some research on the mechanisms of inheritance of heterostyly in oca. What better way to spend the August Bank Holiday weekend?

Due to the attention lavished on my little darlings, (perhaps I should call them ocarinas), I didn't get round to planting the tubers of the other varieties until a bit later. So, although some are starting to form flower buds, they're not as precocious as my own little brats. I've got a fairly good idea of which varieties are the likely parents of my brood, so I'll be interested to see what floral arrangements they have (and I'm not talking ikebana or wedding bouquets).

Some seedlings have reddish sepals, as seen in the following photo:

Another distinguishing characteristic is the presence or absence of little blotches of purple at the base of the leaves where they join the stems. In my other varieties this seems to be carried over into the tubers as dark marks around the eyes. Oca tubers are, like potatoes, modified stem tissue rather than true roots.

Some of the plants with the red sepals have the purple blotches, others don't. From this I deduce that the two characteristics are inherited separately. Whether sepal colour has any influence on tuber colour remains to be seen. If I can avoid my notebook going mouldy or being devoured by slugs, I should have an answer to this by late autumn.

Here's a stem with purple marks at the leaf axils and reddish sepals (honest).

The reclining pose is due to the effects of wind and rain and the twine is an attempt to stop it flopping any further over its comrades. What is it they say about the British climate? Ah yes - one of the best for growing crops and the worst for harvesting them. I'm not even sure about the growing bit any more.

And this is one without blotches, but possessing purplish sepals. Still vertical - so far, thanks to the sheltering embrace of the maukas.

I've noticed what appear to be a couple of fertile pods developing on 0916 and 0917, so I'm keeping a close eye on them. If there's anyone out there who is studying their own pod-laden ocas with similar excitement, it's worth sharing a few tips. The first thing to be aware of is that oca pods are explosively dehiscent, that's to say they pop open and forcefully scatter the tiny seeds. You can forget trying to find them afterwards. Like an overprotective parent, I feel they are a bit too precious to be allowed out on their own. The only answer is to individually bag the pods or harvest them when the seeds are ripe, or nearly so. Oh for the simplicity of big, seedy potato fruits.

Back in 2007, I found bagging the pods individually exceeded my levels of dexterity, raised my blood pressure and expanded my range of expletives. It also threatened to damage the very pods I sought to protect. I decided to opt for the nick-of-time harvest method instead, storing the almost ripe pods in a Petri dish. By placing said Petri dish close to my ear, I was able to hear, on more than one occasion, a Liliputian ping, as a pod ripened and then shattered before my very eyes - I mean ears. If, as I hope, a multitude of pods are formed this year, I may revise my options and try and bag the flowers.

Here's a ripening pod on 0916. Sometimes the seeds are visible through the walls of the ovary and persistent calyx as little bumps. Each bump consists of a seed wrapped in a pale green fleshy aril. Looking at this makes the seed appear under ripe, but the pod may actually be close to dehiscence. Beware!

Just after this picture was taken, we were hit by more wet and windy weather. I could hardly believe it when this little pod, pregnant with possibility, was from its mother plant untimely ripped. Oh calamity. A bit of diligent searching revealed the squashed and soggy pod lying beneath a pile of sprawling oca stems. And there, like a pearl in a pulverised oyster, sat one tiny seed.

You can forget about your new season Beaujolais and associated hullabaloo - to me this event has much deeper resonance. Excuse me mixing my drinks, but here's to Chateau Mouton Radix 2009 - let's hope it's a good vintage.

From what I've read, the original Radix pollination method, involving shoving one flower into another, can be improved upon. I shall go away and see whether I can develop a method with a little more finesse and a little less, well, brutality. I'll keep you posted.

Friday, 14 August 2009

My Maukas Just Multiplied

I have just received, courtesy of fellow conspirator Frank van Keirsbilck, cuttings of two new varieties of mauka. The two varieties come with simple, yet profoundly descriptive Spanish names: Roja (red) and Blanca (white). Roja looks similar to CIP 208001, the variety which both Frank and I grew from seed last year. Blanca lacks the redddish coloured stems of Roja and 208001 and has noticeably paler leaves. I wonder whether the flowers will be white, rather than the pale purple of 208001.

I like a good picture as much as the next phytophanatic, but I think I'll restrain my snap-happy tendencies until the new starlets are a little bit bigger and more photogenic. For now I've got them in intensive care until they're properly rooted. When they've got a good crop of leaves, I'll host a suitably glitzy coming out party. You are cordially invited. RSVP.

Monday, 10 August 2009

Achira - You Can with a Canna

If it looks like a duck and quacks like a duck, then it probably is a duck. So my achira, which looks like a bog standard purple canna, is indubitably a canna, just like the ones gracing a roundabout near you. Mine came with the moniker "achira morada", purple achira. I've had it for years. At one time achira was afforded the honour of species status, Canna edulis; now it seems to be considered a variety of Canna discolor or Canna indica. It comes from - you've guessed it - the Andes.

For some peculiar reason I haven't managed to kill my achira, despite letting it dry out, get frosted and most recently, leaving it in a greenhouse to cook at about 48 degrees Celsius for several days. I wouldn't say that achira thrives on any of this treatment, but it is remarkably tough. I haven't yet tried it underwater, but I've got form, what with the mashua and oca waterlogging debacle last year.

The most shameful aspect of all this is the fact that I have never, despite ample opportunity, actually got round to eating its rhizomes. This year I intend to remedy that oversight. By all accounts they have a pleasant sweet taste and go well with roast guinea pigs, although they take a while to cook - the rhizomes, I mean.

Achira is famed for having the largest known starch grains in the plant kingdom, ones that are visible with the naked eye. It's cultivated in SE Asia, particularly in Vietnam for the production of transparent noodles and also in Australia where it's known as Queensland arrowroot. Because the starch grains are so large, it's easy to grate the rhizomes in water and collect the starch grains with simple home made equipment and produce a high grade starch. My infamous crumpled shirts may be a thing of the past....

I think it might be worth dashing into the local park's undergrowth to explore the edibility of various other ornamental cannas. William Woys Weaver has been doing the same with dahlia tubers, although I think he's growing his own rather than raiding other people's flower beds. Yes, dahlias are perfectly edible. While you're at it, why not try the same with amenity plantings of sweet potatoes such as Blackie, which definitely form useable tubers. Not so much guerilla, as gorilla gardening. You could always beat your chest and pant-hoot if the authorities try and stop you.

Here's my achira, just prior to me lopping off a chunk to send to Frank van Keirsbilck. The keen eyed among you may notice a hog peanut seedling has insinuated its way into the pot. That spell at 48 degrees Celsius seems to have done no permanent harm.

And here's proof, if proof were needed, that this is none other than a canna, with a typical canna's physiognomy:

Those rhizomes look promising, if somewhat stunted and, er, a bit tough. Still, I've eaten mashua and survived, so achira ought to be sweet confection in comparison.

Saturday, 1 August 2009

It Might As Well Rain Until September

Well, the sun has yet to return in any meaningful way, but I did manage to get a photo of one oca seedling's flowers, hanging somewhat disconsolately in a shower-induced sulk. They were a bit too wet and tight-lipped to determine what kind of stylar arrangement they had, but I suppose I can wait until the rain subsides and the sun returns. There is talk on the radio about a possible improvement in August - maybe, then again maybe not. Too late for the potatoes - we hacked off the blight-blasted foliage the other night.

Glass half full moment: at least we're not growing cereal crops as a subsistence staple - I might fear for my expanding waistline if we were. Phytophthora notwithstanding, tubers as a staple make a lot of sense in our fickle and vacillating climate. Hence the Radix project....

Here's a view along the bed full of babes, showing some of the variation in size among the seedlings.

And here's a shot of one of the maukas, all trussed up with nowhere to go. They seem completely unfazed by the weather, be it dry or wet. Nor are they bothered by their incarceration in my hastily constructed makeshift pots. This plant is a proliferating mass of shoots about a metre across.

As I was snapping away merrily (a career in photo journalism, you'll notice, just got even more unlikely), I remembered something I'd read by Tom Wagner. Tom is a tomato and potato breeder in the USA and has created loads of the varieties that grace the gardens of the heirloom tomato brigade. Hell, I've even grown Green Zebra tomatoes myself.

In his potato breeding he is very careful to select for potatoes with superior berrying abilities - no seeds, no new varieties; a similar goal must surely be at the top of my list. Most breeders choose sparse-berrying potato varieties as female parents of crosses, because it's easier to cross pollinate these without having to emasculate the flowers. The result, according to Tom, is that their progeny go on to be poor berry producers. He advocates an alternative approach, selecting parents that are able to self pollinate as well as outcross. As oca is, apparently, an obligate outcrosser, this is going to be a little tricky to achieve. And yet.......

There is a small amount of self fertilisation in oca. A paper I read a while ago suggested that the mid-styled morphs (weren't they headlining at Glastonbury this year?) are able to self-pollinate to a limited degree. They can then go on to produce fertile seeds. Should we be scouring our collections in search of these in order to up the likelihood of producing more new seed grown plants? Are the "crosses" I'm presuming took place merely the result of favourable conditions at the time of flowering and nothing more than self pollinations? Are our plants raddled old workhorses, riddled with viruses which are rendering them incapable of sexual reproduction, hence the aborted flowers? More flowers will soon be on their way - time to crank the starting handle on the Radix oca database, whip out the hand lens and get down, serious and dirty, in pursuit of data.

PS. Tom Wagner is coming to Europe this autumn.......

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