Are you sitting comfortably? Time for a quiz. What tuber is small and round and yellow and grows in the Andes? Answer: ulluco. What tuber is long and pink and grows in the Andes? Answer: ulluco. What tuber is long and yellow with red stripes and blotches and grows in the Andes? Answer: ulluco. OK, enough already. You get the drift. Ulluco tubers are amazingly diverse in appearance. As if to prove the point,
look at these, which don't really fit into any of the above categories.
Diverse as they are, they seem to share at least one vital characteristic - charisma. By that I mean you'd have to be a fairly stony hearted individual not to want to grow and harvest objects of such exquisite beauty. The tubers seem to glow with a subtle intensity, as though illuminated from within. They're the Ingrid Bergman to oca's Marilyn Monroe.
So that's why I started growing ulluco. It's an infatuation that began even before I became obsessed with oca. I think my first tubers came from Ken Fern of Plants for a Future. Then HDRA actually offered the lemon yellow round variety in the year following the oca members' experiment I mentioned previously.
Although they are both in different families, oca in the Oxalidaceae, ulluco in the Basellaceae, they are perhaps alike in all the wrong ways. Unlike oca, ulluco flowers during the long days of summer and does so regularly. Like oca, however, it tuberises during short days and yields are usually disappointing - very disappointing. Unlike oca, the flowers aren't exactly showy. They're small and to use estate agent speak, "quaint". Cross pollination involves getting down on your hands and knees with a pair of tweezers and a magnifying glass. I've tried this, but I gave up after about my thousandth attempt. So seed production is unheard of? Yes, except in Finland. Finland? Yes, Finland. Back in the 1980s some researchers at the University of Turku managed to produce the first documented ulluco seed crop. They also managed to get some of them to germinate.
So how did they achieve this major coup, while I grovelled, arse in the air, transferring pollen from one flower to another with zero success?
There are two main factors that conspire against those of us who would breed new ullucos. Firstly, the plants are usually riddled with viruses. A brief inspection of most ulluco foliage reveal obvious signs of viral infection, the curse of vegetatively propagated crops. Some plants look thoroughly peeky, with pock marked or mottled foliage and yields decline towards zero with the passage of the years. Suddenly pot noodles seem like the easier option. In fact there a group of viruses which are shared by oca, ulluco and potato which have all been rubbing shoulders in the same fields for thousands of years. So maybe my original plan to transplant a diverse and sustainable tuber polyculture from the Andes to the UK could prove a little bit more challenging than I originally envisaged. Virus infection often renders plants infertile. Those hundreds of ulluco flowers I lovingly pollinated were in all probability firing nano-blanks. Luckily getting rid of viruses is not too difficult. I plan to have a go later on this year.
Another stumbling block that the Finnish researchers highlighted was that ulluco often exhibits polyploidy, where additional sets of chromosomes get incorporated into the nuclei of the plant's cells. This may confer advantages on the plant such as increased vigour and environmental tolerance, but does nothing for aspiring plant breeders like yours truly. Some ulluco plants are diploid, that is they have the normal two sets of chromosomes, which divide up nicely when pollen and egg cells are formed, each containing half the original genetic complement. In theory at least, these may able to produce fertile seeds. Most seem to be triploid, which means an extra set of chromosomes has crept in and during meiosis (remember that from school biology classes?), the chromosomal equivalent of a collapsing rugby scrum breaks out. The upshot is that these plants are functionally sterile. This sometimes works to our advantage. Diploid bananas, for instance, have large and extremely hard seeds, but I doubt you've ever found any in the fruits you've eaten. Cultivated bananas are sterile triploids. Great for the Windward Islands, perhaps, but a conundrum for banana breeders. Likewise for budding ulluco obsessives. It's possible that tetraploid forms may exist as well. You can't tell which is which just by looking. This ain't going to be easy........
Perhaps Edith Piaf would not have sung "Je ne regrette rien" with such passionate conviction had she taken up ulluco breeding as a relaxing pastime to while away the long summer evenings. The French, of course, being keen vegetable growers, have experimented in the past with this and other Andean crops. Consult The Vegetable Garden by MM.Vilmorin-Andrieux for a plus ca change moment, tinged with the sobering realisation that these plants often fare no better now than they did then. Courage mes amis! Together we can crack it.
Ben Gabel of Real Seeds has been selecting ullucos for several years and his efforts are definitely yielding results, yield being the operative word in all dealings with ulluco. This is one of his selections, 'Cusco Market', which has given crops of 2.5 kilos per plant. Believe me, that is impressive progress. Most of the time 25 grams would be closer to the mark, maybe less. Maybe none.
So anyway, what was the fate of the Finnish ullucos? All gone, I'm afraid. When the Finnish research finished, the Finns bade their ullucos a fond farewell. When I contacted the University of Turku, it turned out that none of the original plants, seedlings or seeds survive. Perhaps some wacky veg enthusiast from Suomi would like to prove me wrong by declaring that they smuggled out the last plants and seeds and have been growing them in a secret location for the past 20 years. They are now well along the road to creating a new, long day adapted variety and are ready to share their efforts with the world. Would that individual please contact me immediately!
So there you have it, a wonderfully diverse crop plant, which rarely if ever sets seed, is infected by debilitating viruses, gives improbably small yields and is, in its diversity, exquisitely beautiful. Why do we put ourselves through this grief? I think this picture, kindly provided by Frank van Keirsbilck sums it all up:
Although ulluco breeding sometimes feels like Mission Impossible, I believe we should keep trying; a pot of steaming ulluco might one day be a rib-sticking repast for hungry Brits. Our current food supply system will self-destruct in the next five seconds. Good luck Jim.
If removing the viruses doesn't help you could look at getting root tip squashes done and have the chromosomes counted.
This would allow you to identify your diploid, triploid,and tetraploid lines and then breed diploid to diploid and tetraploid to tetraploid. knowing what you are working with would save you a lot of time and effort in the long run.
The triploids could also be treated with Colchicine to produce more fertile polyploids. doubling the chromosomes also has an affect on plant morphology and vigour and could result in larger tubers being produced.
Worth a try?
I agree that determination of ploidy level would be very useful. Root tip squashes would be ideal for this. I wish I had more time, oh and money for all of this. We need to develop a database of all the accessions knocking around in Europe using the descriptors developed at CIP as well as working out correct ploidy levels.
Chromosome doubling seems like a good idea worth attempting with the tripoids, although my understanding is that this would be most effective with allotripoids (AAB) rather than autotriploids (AAA). Correct me if I'm wrong. I don't know, but am assuming that ulluco is an autotriploid, the product, perhaps, of dipoid x tetraploid crosses. In some cases tripoids can actually be moderately fertile. If potatoes are anything to go by, then day neutral traits are recessive. Sow and grow, sow and grow. We also need botanical seed and varieties from the southernmost range of the species. Watch this space (but not too often).
Most of my research into chromosome doubling is in the field of rose breeding and I'm no expert, but it is usually applied to diploid/tetraploid crosses, so it may have some benefit. And as you say, triploids are generally moderately fertile.
I would suspect that the triploids are better used as pollen donors than seed parents. Triploids would probably produce some fertile diploid and tetraploid pollen and could be used as pollen parents on both diploid and tetraploid selections.
I will be working with Ulluco myself this year (thanks to Catofstripes for the triad). I'm interested in developing it as a perennial leaf crop, more through selection and development of an appropriate cultural practice, but I hope to obtain seed myself some day.
I may need to collect a few more varieties first but at least I have a start on it now. A day length neutral selection would definitely be something worth pursuing.
keep us posted, and let me know if I can help.
Yes, ulluco can be damnably frustrating to grow and does seem to be very susceptible to slugs and snails. The realist in me thinks this is sufficient evidence for abandoning growing it, the optimist hopes for better adapted, more vigorous varieties.