Use of seed protein polymorphism for discrimination of improvement level and geographic origin of upland rice cultivars

Grain proteins from 58 Brazilian and nine Japanese upland rice cultivars (O ryza sativa L.) were electrophoretically separated by sodium dodecyl sulfat e-polyacrylamide gel electrophoresis (SDS-PAGE). Densitometric scanning of the electrophoretic profiles permitted the estimation of the relative conce ntration of 16 protein fractions, which were used as variables for the calc ulation of Fisher's canonical discriminating functions. Significant differe nces between mean values of protein fractions were useful in distinguishing Brazilian and Japanese cultivars, as well as improved and non-improved Bra zilian rice cultivars in scattered plots. Electrophoretically detectable pr otein polymorphism in rice grain can indicate geographic origin as well as breeding improvement level of a cultivar. Improved cultivars were those rel eased by plant breeding institutes.