Population genetics of cultivated common buckwheat, Fagopyrum esculentum Moench. X. Diffusion routes revealed by RAPD markers.

Diffusion routes of common buckwheat were investigated by constructing phylogenetic trees based on variability of RAPD markers among 46 land races and two natural populations of the ancestor. Thirty two primers out of 40 generated reliable RAPD bands, 295 in total. The percentage of polymorphic bands was the highest (45.9%) in southern China, the region in which buckwheat originated, and it declined sharply from southern China to the peripheral range of buckwheat cultivation. Phylogenetic trees for land races were constructed from RAPD variability by the unweighted pair group (UPG) and neighbors joining (NJ) methods. They suggest two major routes of diffusion of buckwheat cultivation; one from southern China-->northern China-->Korea-->Japan, the other from southern China-->Bhutan-->Nepal-->Kashmir-->Karakoram and the Hindukush.