Genetic Polymorphism in Natural Populations of Avena fatua and A. barbata

Abstract

IN a previous paper¹ estimates of the degree of polymorphism at four marker loci and the between and within-family components of quantitative genetic variation were reported for several natural populations of Avena fatua and A. barbata from a small region of the Central Valley of California. These data indicated that the two species differed markedly in population structure; populations of A. fatua were highly polymorphic, in contrast to monomorphism in A. barbata, and were genetically more variable with respect to the quantitative traits studied. We report here the results of an extensive survey for polymorphisms in Avena populations in California. The primary aim of the survey was to obtain comparative data on geographical variation in the patterns of polymorphism in A. fatua and A. barbata and to ascertain how such variation relates to climatic variables, the relative abundance of the two species, and so on.