SEED PROTEIN HOMOLOGIES AND THE EVOLUTION OF POLYPLOIDY IN AVENA

Abstract
Crude seed protein of the nine oat species was fractionated by disc electrophoresis on polyacrylamide gel. Correlation coefficients calculated from optical density curves obtained from the stained gels showed that individual species possessed characteristic, albeit variable, profiles. Pattern variability among and within species was greater in the case of the diploids than in the case of the polyploids. The very few profile types in A. strigosa 4x and in the hexaploid A. sativa suggested that the variation in these polyploids is due more to independent origin of the types than to differentiation following polyploidization. Virtual identity between individual A. strigosa 2x and 4x profiles suggested a strict autopolyploid origin for some 4x types while complementing pairs of A. strigosa 2x profiles indicated an intervarietal origin for other A. strigosa 4x types. A diagnostic band at 11.0 cm in the profiles of A. magna and A. murphyi suggested that these species rather than A. strigosa 4x had functioned as the tetraploid parent of the hexaploid A. sativa. The profile of A. murphyi complemented by a specific A. strigosa 2x profile simulated a specific A. sativa type. The adaptive success of the genus is assessed in the light of variation and homologies in the seed protein patterns of the various species.