Abstract: Two hundred and eighty accessions of indica rice landraces from 14 provinces in China were analyzed using 78 microsatellite markers distributed across the whole rice genome. The genetic structure of indica rice landraces was studied by Powermarker, Structure 2.2 and Popgen 32 softwares. The 280 indica rice landraces were classified into six groups based on Nei′s genetic distance, the indica rice landraces of adjacent provinces were massed in same larger groups and those of each province were clustered together in same small groups. The genetic basis of indica rice landraces in same province was similar. But the indica rice landraces of Shaanxi were clustered in two groups and those of Taiwan in three groups, indicating their genetic bases were complicated. The 280 indica rice landraces were classified into four groups by Structure 2.2, and those of the provinces with near geographical position were clustered in the same groups. But the indica rice landraces of Shaanxi and Taiwan were dispersedly clustered in to different groups, which was similar with the result analyzed by Powermarker. The result analyzed by Popgen32 showed that 280 indica rice landraces were classified in to four groups at the level of 0.27, the landraces of adjacent provinces were clustered into same small groups or big groups except these from individual province. The results analyzed by three softwares were mainly accordant except partial difference, which can complement each other. The indica rice within a province was clustered together into small same groups, the genetic structure was correlated with geographical place. The genetic bases of indica rice landraces from Shaanxi and Taiwan was complicated.

Key words: Indica, Rice landrace, SSR marker, Genetic structure