Abstract
To determine the characteristics of cultivated rice in ancient Japan and the origin of Japanese rice, polymorphism analysis using microsatellite markers was carried out on 73 landraces of Japanese rice which were considered to conserve genetic diversity. Four upland Chinese varieties and eight landraces from Asia were used as standards, which had been classified into Indica and Japonica based on morphological and physiological characteristics. Eight microsatellite markers (RM1, RM20A, RM20B, RM30, RM164, RM167, RM207 and RM241) were used. Japanese landraces were classified into 2 major groups, Indica and Japonica. The 8 landraces belonged to Indica while the others belonged to Japonica. Japonica was classified into 3 minor groups; upland rice group (J-A), combined group of upland- and paddy rice (J-B) and paddy rice group (J-C). Group (J-B) was further divided into two subgroups, upland (J-B1) and paddy rice (J-B2) which correspond to tropical and temperate Japonica respectively. As the results show, “Furuwase”, “Fukubouze” and “Sekitori” upland rice are closely related to paddy rice of the temperate Japonica group that may have been derived from paddy rice. The eight microsatellite markers used in this study were found to be effective indices for the classification and discrimination of the rice landraces cultivated in Japan.
