CHLOROPLAST GENOME DIFFERENTIATION IN ASIAN CULTIVATED RICE

Restriction endonuclease analysis of chloroplast DNA was carried out to clarify the chloroplast genome differentiation between Asian varieties of Oryza sativa. Based on the restriction fragment patterns obtained with six endonucleases, i.e., EcoRI, HindIII, PstI, PvuII, SmaI, and XhoI, chloroplast genomes of 68 local varieties from 15 Asian countries could be classified into five types (types 1, 3, 10, 11, and 12). Among these types, four length mutations and two base substitutions were found; these changes were located on the PstI physical map of rice chloroplast DNA. In a dendrogram showing genetic relationships among five chloroplast genomes, they are mainly divided into two groups, which we have named as the Japonica (types 1, 11, and 12) and Indica (types 3 and 10) chloroplast genome groups. Both groups are distributed widely in Asian countries. The Japonica isozyme group classified by J.C. Glaszmann (1985. Rice Genetics. International Rice Research Institute, Manila, Philippines. pp. 83-90) carries only the Japonica chloroplast genome, whereas the Indica isozyme group contains both Japonica and Indica chloroplast genomes.