Friday, 11 June 2010

Great Ocaspectations (1) Overdosing on Oca

Here's a view of my oca seedling bed as it looked a couple of weeks ago. Each pot contains a single seedling raised by yours truly this year, from the seeds I harvested last autumn. It may or may not be an idle boast, but I reckon that I've now got the largest collection of oca germplasm in the whole county of Cornwall. It all looks uncharacteristically neat and tidy, which rather belies the frenetic panic with which they were planted a few weeks ago.

Some friends had invited us over for tea in their lovely moorland garden. It was a glorious afternoon, with the hot and penetrating sunshine moderated by a pleasant breeze and an almost alpine aspect. I was aware that afternoon was passing into evening, but the sandwiches, cakes, drinks and good conversation made the thought of lifting my corporeal bulk from the lounger even more unappealing. The sun's rays were weakening - and so was my enthusiasm for oca planting exploits. Oh well, tomorrow perhaps? I was gently but firmly reminded of my promise to get the job done. Suitably chastened, I hurried home to collect seedlings, pots and other equipment and get to work.

Working feverishly to plant and label them all before the remaining light faded, I was reminded of Kirosawa's film Dersu Uzala. In one memorable scene, the Nanai hunter saves the life of the Russian army officer Arsenyev by rapidly building a reed hut to protect them when they are caught out by an unexpected twilight blizzard. If I'd stopped daydreaming and searching for poetic comparisons, I might have got it finished a bit sooner. Thanks to the diminishing light levels I can be fairly certain that my attempts to distribute the seedlings randomly have been successful - if more by accident than design.

By my calculation there were approximately 80 oca seedlings to be housed - the products of semi-controlled crosses - that's to say I knew who their mothers were, even if their dads were strangers to me. I attempted to grow ten seedlings or more of each variety, but some failed to come up or were scythed from below by damping off fungi. That's life. Each seedling from a known mother bears her appellation, RX0909 for instance and then an additional number to distinguish the siblings from one another - 1,2,3 etc.

Ah, but I'd reckoned without another 40 seedlings whose parentage was entirely unknown and I had sown during a what-the-hell moment back in the early spring. Suddenly there they were, pleading with me for a stay of execution - till the autumn at least. There was only one thing for it - I'd have to fit them in somewhere, somehow. No wonder I was working at such a breakneck pace. These seedlings I gave designation RX1001 , 02 and so on. I planted them nearby, turfing out, literally, some other less worthy candidates, a bunch of chillies. What is abundantly clear is that this relationship is entirely one-sided - I am at the beck and call of the ocas. I am their dutiful slave. They've domesticated me.


The canes are there to help prevent the plants from sprawling over and through one another and will also allow me to access the flowers and pods more easily - I hope. The pots will, as they did last year, keep the tubers of each variety separate. Under ideal circumstances I would have been able to give each seedling plentiful root run and space from its neighbours and planted them directly in the ground. Unfortunately, that luxury seems to have eluded me yet again. Anyone who has tried determining the provenance of stray oca tubers scattered through a Somme-like plot will know why I have opted for this horticultural apartheid. I have earthed up the stems once so far and will do so again, in the hope that this will encourage the development of tuber-bearing stolons, just like with potatoes. The bare soil, by the way, will be mulched in due course.

What with these seedlings, the tubers from last year 's seedlings, the wrinkled old retainers and new arrivals courtesy of Frank van Keirsbilck, I must have planted around 140 genetically unique individuals this season. Frank managed to get good germination from the seeds produced by my plants of "Pink Dragon", the variety he raised a couple of years ago. So that adds another 90 or so individuals to this newly evolving secondary centre of oca diversity in NW Europe. I hope we're getting up to the kind of numbers where we might start to see some interesting new traits appearing. We're also reaching the point at which some serious winnowing of duds needs to occur.

But before I get too trigger happy, it is probably as well to pause and consider what combinations of which traits might actually be desirable in those oca seedlings that escape the indignity of being untimely ripped from their pots. Here goes:

1) Early tuber formation during long days/ high yield (large tubers)
2) Profuse and early flowering
3) Vigorous and disease resistant
4) Good tuber quality and flavour

1) The main obstacle to oca's adoption as a food crop at our latitudes is its inability to form tubers during the long days of summer. A handful of marbles harvested in October can only lead to unfavourable comparisons with the potato and contribute to oca's notoriety as an "experimental crop". No, this just won't do: I'm looking for day neutral forms, or ones that can tuberise when days are significantly longer than 12 hours. I won't rest until I find one, preferably several. Perhaps I ought to set a harvest date some weeks before the end of September, lift the plants and keep those bearing the largest tubers.

2) At this stage in the game it is vital to obtain precociously floriferous plants with the ability to set a plentiful crop of pods. Seeds contain novel and unique combinations of genetic material and are the raw material upon which selection, natural or otherwise, works. Can't have too many seeds.

3) Vigour and disease resistance are also very important. Differences in vigour start to show early on in a seedling's life. I suspect vigour could be linked to early flowering and - maybe - early tuber formation. If some seedlings are small and puny and prone to damping off, chances are their offspring will inherit this weakness. I'll weed them out, so that their contribution to the next generation is nil. I'll be watching disease and pest susceptibility too.

4) At the moment my main concern is to get plants that reproduce efficiently, both sexually and vegetatively. That said, I ought to check that the tubers resulting from my mini breeding programme are of acceptable quality and are not too bitter, fibrous or unpleasant in any other way.

In my next post I will discuss what little I know about oca genetics and how I might use this knowledge in my breeding programme.


9 comments:

Nellie said...

Yours is one of the most knowledgable blogs I read... so I was wondering if I could ask for some unrelated advice?
I've been looking at some horticultural courses but I'm seriously restricted by life at the moment. I stay at home with two small children and don't drive. I've been looking at online courses. Do you think any of these sort of courses are likely to be of any use? I really want to take my love of the garden/allotment to a level where I can point a 'career'in this direction but I've no idea if this is possible or how to go about it. I'd really really appreciate any advice!!!
(sorry for leaving such irrelevant comments on your blog)
Nellie x

IAP said...

Ah! such order! And on such an impressive scale. I suspect you will have to create the mother of all spreadsheets to record all of this at the end of the year. Either that, or get a really big jotter.
Any plants that tuberise early might give themselves away by dying back earlier. Or perhaps you could carefully slide up the bottomless pots to check for early tubers. Oops the taper goes the wrong way- but next year... ...used upside down...
Now Nellie, if you did a course on the internet, I bet you wouldn't learn to invert your oca ring-culture pots to allow early tuber inspection!

Rhizowen, I look forward to reading your post on oca genetics.

Mark said...

Could you get anyone to genotype each of your ocas? That could be useful in knowing what is what, and what to cross?
Or maybe just the ones with selected desirable traits.
PS how are the northern talet seeds?

Rebsie Fairholm said...

I have to admire the special kind of fortitude it takes to work on a project like this - looking for the breakthrough (or collection of breakthroughs) which will bring this recalcitrant crop kicking and screaming into the realms of mainstream vegetables. I have it pretty easy with my projects ... they've had 11,000 years worth of work done on them already, yields and flavours are sorted and all I have to do is tinker with the colours and shapes. To take on a crop which is full of potential but hasn't quite got there yet is very brave and valiant. And vital - because work like this has to be done by someone who's prepared to do it for love rather than money. You write about it so compellingly too.

Looking forward to reading about the genetics.

Vegetable Heaven said...

I grew oca for the first time last year from 4 tubers I was sent in a seed exchange. I have to say, I loved the flavour. One of my criteria in deciding which to replant was that the reddish ones made very nobbly tubers - a nightmare to prepare - but the orange ones just needed a scrub. I only replanted orange!

Mine only produced 3 flowers between the 4 plants.

Mark said...

Some information that may be useful. Scientists have found chemicals that are synthesised by mosses that stop slugs eating them. These are called oxylipins.
I was wondering if one could gather some moss from a suitable soggy location e.g. Cornwall and infuse it into hot water extracting, hopefully, these chemicals. They could then be sprayed upon crops which would then not be ravaged by the Slugs.
Worth a try, little else deters them, and you need to protect the oca seedlings!

Rhizowen said...

Nellie - Flattery will get you everywhere. It's not an irrelevant comment by the way!

A good theoretical grounding is very useful for most disciplines, especially for understanding of basic life processes (in the case of plants, photosynthesis for one example). Then combine that with practical experience and enthusiasm and you move into the area where art and science meet. You become an amateur (lover) and parctitioner of applied plant science, which is what horticulture is. It's brilliant.

I haven't looked at any online courses, so couldn't comment on their quality. Careers in horticulture can be very rewarding, but, sadly, earning a comfortable living from them can be more of a challenge. Which you will rise to with courage and grace, no doubt. Working with schools and community groups can be very rewarding. If gardening is something you really enjoy and you can communicate that enthusiasm to others, then there's much enjoyment to be had. People can be boring - plants - never.

IAP - don't know what came over me - moving from the shambolic to the regimented. Getting results for the A1 size jotter I've just purchased maybe.

Mark - that's an idea I might consider in future years - thanks - oh and the stuff about the mosses and oxylipins (@ Nellie: practical horticultural science in action ). I know of plenty of big clumps of Dicranum scoparium hereabouts.

Rebsie - You're too kind. Valiant is not a word I usually associate with myself, but others see things differently I suppose. I was thinking along the lines of foolhardy or maybe even bonkers.

Vegetable Heaven - glad you enjoyed the ocas you grew - a lovely plant in my opinion. With a little help from its human friends, I'm sure it will adapt to our gardens and dinner plates quite well.

orrflo said...

Slugs messed up my plants,so I lost some, I should have some seventy left (from seedlings). What bothered me a bit, and will probably be out-selected after a while, was that germination of the seeds was quite hazardous, some already had a four weeks growh period, while others just germinated. Even considering the very dry weather, they are growing great, and I will transplant them soon into bigger pots. Most of them seem to have a familiar reddish-yellowish stem, some however are greener, and others have darker-coloured leaves. What I'm aiming for is that some seed will be set over here, under these slightly warmer and drier circumstances. I think the higher air humidity contributes to the forming of the seeds, and not the temperatures.

Nellie said...

:) thanks for the words of encouragement! Life is long, I'll see where it takes me (hopefully somewhere green and lush). In the meantime i'll keep reading your posts and hoping one day when i grow up i'll be half as clever ;)

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