Vavilov concluded that each crop has a characteristic primary center of diversity which was also it s center of origin. Vavilov recognized twelve areas in which he argues all of our major crops had been domesticated. Vavilov s ideas were very influential and still form the basis of our present understanding of crop domestication. Therefore, if the first assumption is correct, then the idea of 12 centers of origin is replaced with a geographical continuum of evolution and domestication. There are now examples where there is little connection between the source of the wild ancestors, areas of domestication, and the areas of evolutionary diversification indicating that species may have originated in one geographic area, but were domesticated in a different region, etc.
Seeds breed true on entire plant.
Both breeders subjected mixed populations of plants to a natural epidemic of the disease by growing the plants in soils in infested soils and selecting the survivors. Devoted over 50 years to improving soybean yield, nematode and insect resistance. The modern industry of plant breeding is changing. International ag research institutions. Prior to 1950 - most varieties developed by public institutions.