This is astonishing. Luigi said that a dominant meta-narrative in our circles is that selection and breeding displace diversity. Another is that well-bred monocultures improve yields. There’s always been an opposing point of view, most closely associated with the name of Professor Martin Wolfe. Now no less a leviathan than the United States Department of Agriculture seems to agree.
In a ground-breaking experiment, USDA scientist Christina Cowger made mixtures — blends — of two or more wheat varieties and planted them in experimental plots in North Carolina. The results?
The blends outyielded the pure varieties by an average of 2.3 bushels per acre. … That’s a 3.2-percent yield advantage. Blends and pure varieties did not differ in test weight or quality across environments, and blends were either beneficial or neutral with respect to diseases.
Blends are also more stable from year to year, a fact that may be behind farmers taking matters into their own hands: 10 to 15 per cent of the wheat area of Kansas and Washington states was planted to mixtures over the past four years.
I’m looking forward to seeing the full published paper.
Varietal mixtures indeed appear to be underutilized. Here is a nice review. Mixtures seem to work best when resistant (but less valuable) varieties are used to buffer senstive (but valuable) varieties. At least that’s what is reported for Kansas by the USDA and was reported for rice mixtures in China.
Thanks for the links, although the APS one could not be found and the Nature one is behind a paywall. Can you send me the PDF and I’ll look for an operational link.
This is a topic I have been interested in for a long time, and it is really heartening to see mainstream (USDA) take an interest.
I think the Chinese example fits your analysis well, but the east German barleys do not, as there was no “valuable” varieties and even if there had been, it would be kind of hard to separate them out with a combine harvester! It’s different when workers are harvesting individual rows of ricce by hand.