Mostly I see differences in node spacing and stem thickness, which is typical for a lot of plants. I haven't noticed color differences at all on the outsides of the stems, but I haven't harvested multiyear crops of wasabi before now, so I haven't had a chance to dissect and examine the effects of this variable culture to the insides. My plan is to work on various ways of keeping the plants happy first, and once I've established that I can reliably produce crops, work on improving the harvestable product.
This year's pretty crazy in many ways, but assuming I can put the time into this project I want to, I plan to make divisions this spring to start some plants on what will eventually be a three year rotation. During the summer, and starting in late spring before the plants die back, I plan to experiment again with swamp cooling methodologies. And then in the fall, and again next spring, I plan to harvest and dissect some stems.. At that point I'll have better information on what I'm doing to the all-important stem with these extreme cycles. I'll be looking for variations in color, flavor, pungency, size, and aesthetic desirability. Whatever I get from this set though, it's still fun to me to be growing this cool, wet, alpine plant in a dry desert of temperature extremes with minimal effort and expense.
I expect to have lots of extra offsets when I harvest, so I hope to put some to cool water culture: natural beds with organic inputs, classic hydroponic inputs, and aquaponics with cold water fish. My previous experiments showed that the plants were far more resilient in organic media than a more mineral based one, but I'm hoping that with better water temperature control I can better simulate agricultural conditions traditionally provided in Japan.
I've also talked with people in Japan about getting new material from various regions of the country, but I was having trouble getting a current import permit, and right now it's entirely impossible...
