Tuesday, 13 December 2011

Assessing Some New Oca Varieties

Back in spring Frank Van Keirsbilck sent me a package of tubers to supplement my usual planting. These were grown from true seed, and thus relatively untested as productive varieties. Last week the weather was still holding frost-free and perfect for continued tuberisation, but I decided that lifting them early would be a good idea. They are going to be used solely for propagation material, so hanging on for maximum tuber size would be no advantage. In fact, lifting early would be better for identifying any less day-length-sensitive individuals. Also I was impatient.

This is "NZ003", his reference variety, which he also sent me, already showing a good yield...

The plants have been rigorously neglected all season as part of their selection process. They were planted in newly cleared ground, then left unweeded, unwatered and unattended.
By the way, if anyone doubts Oca's ability to outcompete weeds, have a look at this...
... Folding back the mass of foliage reveals completely clean soil.

Anyway, as would be expected there was a lot of variation in tuber appearance...

and also in productivity. A couple of plants expired during the growing season, some produced feeble crops, while others challenged the reference variety on productivity.  I've listed all the varieties, with their crop weight on this Google doc if you want to have a look at the details.

Of note would be 026 which produced this fasciated tuber...

...and 023, very productive, and many of whos tubers are characteristically elongated and possibly fasciated. This seems very interesting, and could be a route to increased tuber size.

014 and 008 yielded beautiful clean tubers...

This last one is not one of Frank's. It's grown from slips taken from the pink striped tuber that I got from Joel Carbonnel. Strangely the tubers are neither striped nor pink, but show varied colouration, and tiny flecks of purple at the ends of some eyes. It seems as if there is some instability going on, so this could be  one for development. In any case it's a good cropper.

Meanwhile my main bed of 'eating' varieties was frosted back the other night, so they'll be ready to lift in time for Christmas.


  1. Excellent work Ian. I reckon there's enough diversity in oca to provide us with some superior varieties. I wish I was as methodical as you when it comes to recording results. Does the other mitt have the word "hate" emblazoned across it?

  2. Yes, I'll try to include the other mitt in a future post!

  3. Ian, nice work there! I had similar results, 023,014 (bigger tubers so this could be somewhat earlier), 015,024 and 010 were the better producers. I couldn't weigh them, mice ate too much and results would be unreliable. Some 50 new varieties from 2011 have been harvested today, I'll still have to photograph and label them, so more info (and tubers) will follow later. Even if we haven't found the holy grail yet, some nice new varieties are beeing created!
    I do like that New Zealand variety as well, and have some new heirloom NZ varieties still growing (only received them by the End of July)