Genetic Diversity and Population Structure in Hashemi Rice (Oryza sativa L.) Mutants Revealed by Morphological and Molecular Markers

Mutagenesis has been one of the effective methods for creating genetic diversity and plant mutants can be significant bio-resources for crop breeding and functional genomics studies. The genetic and phenotypic diversity of 95 selected mutants from 17 mutant populations, obtained from an EMS mutagenized rice Hashemi variety, were phenotypically and molecularly assessed in M3 generation. Phenotypic variation of these mutants showed that grain yield components varied among the selected mutants compared to the control plants. In parallel, genetic diversity assessed by 13 Inter-Simple Sequence Repeats )ISSR) primers showed that the number of amplified fragments per primer varied from 4 (pr1-7) to 11 (ISSR-7, ISSR-11). In general, 13 primers amplified 99 fragments, 50 of which were polymorphic (52.92%). The genetic variation created by ISSR markers within 17 populations varied from 11.11% in HM9 (Hashemi Mutant Line number 9) to 45.45% in HM2. The average molecular polymorphism value was 0.27. In the total genetic variance, 95% of differences were attributed to within-population diversity, and 5% were related to among-populations. The Unweighted Pair-Group Method with Arithmetic mean (UPGMA) trees illustrating ISSR diversity classified the rice mutant population into seven groups, which were further supported by model-based STRUCTURE analysis. In general, the studied mutant genotypes revealed desirable genetic characteristics in populations 13 and 17, with em3h204 and em3h280 genotypes being the most divergent.