The possible role of weed races in the evolution of cultivated plants

Most of our cultivated plants have companion weed races. This phenomenon is so common that it must have some biological significance. In some cases the weeds are the progenitors of the crops, but in many cases we must look for something that could give rise to both the weed forms and the cultivated form together.The weed races have served as reservoirs of reserve germ plasm, periodically injecting portions of it into the crop under conditions that would most favor increase in variability, heterozygosity and heterosis.Presented at a symposium entitled The Origin and Evolution of Cultivated Plants held during the Tenth International Botanical Congress, 1964. Submitted by J. B. Hutchinson and J. G. Hawkes.