Abstract

One hundred and sixty rice varieties from the tidal and flood prone areas of south and south East Asian countries were analyzed. Samples sizes were: 50 varieties from Bangladesh (deepwater, tidal and flood prone rice and modern varieties), 14 varieties from India (flood prone rice), 16 varieties from Sri Lanka (flood prone rice), 7 varieties from Vietnam (tidal varieties), 69 varieties from Indonesia (tidal varieties) and 4 check varieties from IRRI. All 30 primer pairs created polymorphic bands among the 160 rice varieties from flood and tidal prone areas, which indicated that the microsatellites used were suitable for diversity analysis. A total of 337 alleles were detected with an average of 11 alleles per locus and the number of alleles per locus varied from 4 to 21. The highest PIC values were observed for the primer of RM474 (0.91), followed by RM5 (0.82), RM484 (0.81), RM214 (0.81), and RM19 (0.79). Cluster analysis divided the genotypes into four main clusters and six sub-clusters based on geographical origins and ecotypes. Microsatellite clustering (over 30 polymorphic loci) and submergence screening data indicated greater genetic diversity among 160 genotypes for molecular loci and for submergence tolerance. Tolerant genotypes in Cluster-1 are expected to have different tolerance genes. Finding relationship between tolerance and country of origin, highly tolerant varieties (FR13A and FR43B) were found from east India. Genetic diversity analysis among flood prone rice will be useful for identifying the varieties having maximum diversity with submergence tolerance and selected varieties will be useful for further studies.

Keywords: SSR, Genetic diversity, Tidal, Flood prone, Submergence, Rice (Oryza sativa L.)