When Joel Mokyr criticizes Jared Diamond's _Guns, Germs, and Steel_;(posted 8755 days ago)... in the chapters on agriculture [Jared Diamond's] imagination abandons him. How much of the performance of non-Europeans was really constrained by their environment and how much their own making? In Diamond's view, the answer is "all and nothing." Yet one can imagine crops that were manipulated and selected to produce crops that are as unimaginable to us as poodles and sweet corn would have seemed 10,000 years ago. Take one example: among the disadvantages that the indigenous plants of what is now the Eastern U.S. suffered from is a lack of founder crops. Yet he does concede that some of them on the surface could have done nicely, such as a flower named sumpweed, "a nutritionist's ultimate dream" with 32 percent protein. Sumpweed, Diamond explains, did not make it to the rank of corn , potatoes, and rye because it causes hayfever, does not smell good, and handling it can cause skin irritation (p. 151). Are we really sure that these vices could not have been bred out of them? After all, all domesticated plants had originally undesirable characteristics, but through deliberate and lucky selection mechanisms they eventually got over them. Wheat, rye, and maize, which feed much of the world's population, all had humble beginnings...
I think Mokyr misreads Diamond's argument--which is, first of all, not an argument about the disadvantages faced by non-Europeans but about the disadvantages faced by non-Eurasians.
As I understood Diamond's agricultural argument, Eurasia's agricultural advantage had multiple causes. One of these multiple causes was indeed that Eurasia had "better flora (for our long-run purposes: grains with larger seeds). But others were at least as important. Eurasia was bigger. Because Eurasia runs East-West rather than North-South, knowledge about effective agricultural techniques diffuses much more rapidly and successfully. Add all these reasons together and you can see why Eurasia is (still) the most densely populated region of the world, and why the world's diet is based on wheat, rye, rice, and their cousins.
I had thought that one of Diamond's points was that American Indians had done rather well--with corn and potatoes--even though the original flora was not that appetizing (have you ever seen a wild corn plant?). But two heads are better than one. Add Eurasia's large size coupled with easy diffusion along the East-West axis and "better" wild grains and it would have been extraordinary if New World agriculture had been more developed than Old World. Had the American Indians been given enough time, then even with low population densities they might have eventually selectively bred and domesticated sumpweed. But their independent history was cut short in 1500.