Cleaning Up My Act; Radix is Two Today

It is very uncharacteristic of me to restrain myself from opening my Christmas presents until this late in the year.  I've always considered delayed gratification to be one of the most overrated virtues and have acted accordingly.

So how I managed not to harvest my indoor ulluco plants until now is nothing short of remarkable.  I wish the same could be said of the yields I obtained.  Ulluco does seem to be infuriatingly fickle: it doesn't like to be too hot or too dry and slugs seem to enjoy it more than the average ex-pat Andean tuber crop. Then there's its steadfast refusal to form tubers at anything like a sensible time of year. That's why, in sheer desperation, I've taken to growing it on the windowsill in a cool room.  Hopeless - but oh, those tubers are so exquisite.

Another black mark against its name is its susceptibility to viruses. Virtually all the plants I've seen are loaded with viruses.  Which brings me on, rather neatly, to a post which I was intending to publish on ulluco last year, but didn't, for reasons that will become obvious:

Cleaning Up My Act

Not the brisk rub down with carbolic soap that some have suggested I need, but more of an attempt at a bit of in vitro cultivation of ulluco, that iconic Crap Crop of the Incas. The intention of the exercise is to see whether its crap cropping might be ameliorated a tad by eliminating all the nasty viruses that lurk inside both tubers and plants. I've enlisted the help of a friend employed at a local institute of learning - let's call him "M" for the purposes of this post. He's got the requisite technical skills and is keen to help. He's also pretty nifty at fixing gadgets, cars and assorted technical paraphernalia. Maybe "Q" would be a better name: my Aston Martin has never run so smoothly......

This is a virus laden leaf of Ulluco "Cusco Market", with blotches of some sort of mottle virus clearly illuminated by the light behind.

Like potatoes, this is no good at all for the plants and reduces their vigour. Weak plants give reduced yields; in the case of ulluco this frequently leaves you staring blankly at the empty soil in disbelief, like a horticultural Old Mother Hubbard. Viruses are the bane of tuber crops and should be driven from their hosts and put to the sword at every opportunity. Like now.

There's a well-established protocol for this in some Andean root and tuber crops, but firstly we opted for the squint and slice method, which involves the removal of the miniscule growing tip of the plant, known as the meristem. This is usually virus free, as the cells are dividing so rapidly that they outrun the viruses. If said meristem is placed in a sterile growing medium with the right levels of plant growth regulators and vitamins -bingo - you get a new virus-free plant. That's the theory anyway. At least we now have the plants growing under aseptic conditions - the Andes in aspic if you like.

Here are some ocas:

These are ullucos:

Viruses can be defeated in other ways, including the addition of antiviral compounds into the growing medium (which is usually agar based) or by subjecting the plants to higher than usual temperatures, which zaps the viruses, but leaves the plants themselves unharmed. Being of a cautious and sceptical demeanour, I decided that we should, in addition to meristem tip culture, attempt at least one of the other options to give those vile viruses a double whammy that would surely leave them homeless............ Communication ends here. 

In one of those charming little volte-faces, I lost all of the above plants when I opted for an impromptu stay in the local infirmary. At that precise moment (and not a million miles away) the incubator where the plants were stored chose to fail; the combination of several weeks darkness and low temperatures killed the whole lot. I almost cried when I finally managed to struggle in and survey the carnage.  

Tissue culture of plants is not that difficult to do (I managed it) and can be carried out quite successfully at home, using bleach, a pressure cooker and a few other bits of equipment. Sinner, lay down that Sabatier and pick up your scalpel.  So although this experiment ended in failure, I have at least shown that it can be done - should be done.

Oh, and by the way, today is Radix's second birthday. The "terrible twos" await.  No one ever said this was going to be easy.......


Alex Mitchell said…
This is so fascinating – had no idea you could get virus free plants by chopping the tops off. Keep up the crazy experiments! Did you actually get any ulloco to eat? What does it taste like?
The world needs more adventurers prepared to try and clean up these crops. You've shown it can be done. I hope for a successful post on this later this year?
Choclette said…
Don't lose heart, you are doing excellent work.
Anonymous said…
Just discovered your blog, thanks to your responding to a query I had on Twitter. Lovely writing and very interesting. Thank you.

Patrick said…
What a great thing to try! Having virus free ullucos would be a real achievement.

Also, happy blog birthday!
CarpeDiem said…
Wow, I want to try this after I connect somebody for translate.
Otherwise possible I take mistakes, because undestandig.
How can I diagnostic viruses on Oca and Mashua?
I believe some tubers in germany also have viruses.
Thank you very much for this information.
Mark said…
Keep going. We are all inspired by your efforts in the tuberous direction! Ulluco doe sseem to be one of the cursed tubers as regards viruses (or should that be virii?). Tissue culture does seem to be the best way to go, so keep on trying.
So I have been thinking about ulluco & viruses.

Everyone 'knows' that the problem with ulluco is that it gains such a heavy virus load that it is unproductive and indeed produces fewer tubers over time when you grow it, with the yield dropping and dropping each year.

Hence efforts to do virus-free culture. I have toyed with the idea too, and even sent off tubers to a man in a lab (who never returned them).

But now I am having heretical thoughts (must be getting old). You see, my ulluco NEVER has any virus symptoms. NEVER, not once in 10 years of growing the damn stuff. And moreover, I have never, never seen a single aphid or similar virus-transmitting agent of doom on the leaves.

Yet my yields go down. I get from Peru (by means best left unexplained) a new cultivar like Cusco Market, and it gives 2 kg/plant the first year. Then 700g/plant the next year. Then bugger all per plant and finally I don't have it any more.

Right now I'm not sure I believe in the viruses theory any more than in Father Christmas. I know yours do have a virus, but honestly, my plants look just fine. They just don't grow any **$%^£! tubers. And they did the first year I had them.

So... how about this for an alternative theory: The ulluco has a problem with being grown in the wrong daylength. Something goes wrong with the internal daylength / temperature sensing mechanism and unlike other plants we are used to playing with, in this case the effect is CUMULATIVE over several seasons.
Each vegetative cycle it gets worse. So we are not seeing effects due to exponentially increasing virus loads, but due to annually-increasing buggered-upness of the tuberisation clock.

Now this could all be rubbish. But it's not impossible. There are all sorts of funky mechanisms that could do this. And I think we could test by taking some craply-producing tubers, splitting them in half , and growing 1/2 in the right daylength regime for a season to see if it resets things.

(Hmmm.. What would be interesting is if a single season could reset it; we could produce ulluco 'seed tubers' in the correct environment and grow them here for production. )
Rhizowen said…
Hi Alex - plants present you with so many possibilities. the perfect antidote to boredom. I'd say ulluco had an earthy flavour, a bit like beetroot, to which it is distantly related.

Veg Heaven - I'll try my best.

Choclette - Like Gloria Gaynor, I will survive

onebeanrow - thanks for the comment.

CarpeDiem Danke. You can use an ELISA test for the presence of viruses. The Andean tuber complex share a number of viruses. Contact a local horticultural college or university for advice on micropropagation.

Patrick - thanks for the birthday wishes and I'll keep on plugging away at all this as time and resources allow.

Mark - Thanks. It's nice to have everyone offering their support. If nothing else, it makes sense to get these collections established in vitro so they can be cleaned up and categorised properly. I was just particularly unlucky.

Ben - glad your ullucos don't have any visible signs of viruses. I'm envious. It would be interesting to subject them to the ELISA tests or some other virus ID protocol to establish whether this is true. Whether some sort epigenetic effects might be involved in Ulluco Decline (may as well big it up as an actual disease or disorder while we're at it), I don't know. The yields do tail off remarkably quickly.

Something I did notice this year was (following another equipment failure) the temperature in the room where they were growing dropped by at least 10C and some of the lights they were growing under malfunctioned so that there were less far red and infra red wavelengths emitted. Two of the ulluco varieties (one was Cusco Market) began forming stolons and tubers soon after. The daylength remained the same at 14h. That seemed to be quite an interesting result to me, although I haven't had time to ponder or explore its significance, if any.
Julien said…
I'd like to know how you managed to grow meristem from them so easily, and how to make sure the result is free of viruses.
Especially, how an amateur could get the right solution of agar.
Rhizowen said…
Julien - well ulluco is remarkably easy to root from cuttings, although in order to clear viruses you need to excise the a very small part of the apical dome. It's quite easy to set up your own tissue culture lab. Most growing media use a version of MS (Murashige and Skoog) which has stood the test of time, plus various plant growth regulators. There is quite a lot of advice available on the internet - Kitchen Culture kits for example: