Identification of Phenotypic Variation and Genetic Diversity in Rice ( Oryza sativa L.) Mutants

In this study, phenotypic variation and genetic diversity, important factors to decide germplasm for rice breeding, were evaluated among 15 rice mutants attained from the MNU ( N -Nitroso- N -methylurea) mutation. The correlation coefficient values among these phenotypic characteristics were calculated. The results showed that full grain number per plant was the most relevant factor contributing to grain yield per plant, and grain length to width ratio was the key parameter affected to amylose content. Furthermore, the genetic variation among mutants was estimated by Simple Sequence Repeat (SSR) markers related to amylose content trait. Fifty-six polymorphism markers covering across eleven rice chromosomes were recorded with an average of 3.02 alleles per locus. The average value of polymorphism information content was 0.47. By using the unweighted pair group method with arithmetic mean (UPGMA) clustering, four clusters were generated with the genetic similarities ranging from 0.52 to 0.91. The variation among groups was 34%, while the variation among individuals within groups was 66%. Findings of this study provided useful genetic background and phenotypic information of collected rice mutants to breed rice cultivars with improved quality.