Genetic Diversity of Mid-ripen Japonica Varieties II.Comparison of Genetic Diversity of Japonica Varieties Bred Recently in Huang-huai Region by SSR Markers

A total of 42 SSR markers were used to study genetic diversity of 136 Japonica varieties bred during the recent thirty years.Of the 42 SSR loci,33 were polymorphic.All the 33 polymorphic loci revealed a total of 106 alleles.The average number of alleles per locus was 3.2 with a range from 2 to 7.The genetic diversity index of Nei was 0.249,varying from 0.171 to 0.426.The TDj value varied from 0.629 to 0.945,which indicated the differentiation degree of rice indica-japonica was distinct,and most varieties disintegrated thoroughly between Indica rice and Japonica rice.UPGMA cluster analysis showed that at the genetic distance of 0.43,136 cultivars could be classified into two large groups which could be further classified into several sub-groups.Cluster results reflected the relationships of 136 Japonica varieties.