Identification of salt tolerant mutants in rice and their fingerprinting using ISSR markers

Identification and selection of varieties with improved qualitative and quantitative traits has a particular importance in breeding process of current varieties and developing new cultivars. Chemical mutagens provide a diverse gene pool in plant resources and as a complementary tool are applicable in breeding programs. In this study, ethyl methane sulfonate (EMS) was used to create genetic variability in rice (cv. Neda), and the role of gained mutations was examined in improving salt tolerance. M2 mutant lines were evaluated at germinating and seedling stages under NaCl salinity (-1.2 MPa), that was resulted in identifying 9 salt tolerant lines. The lines along with original wild cultivar were also evaluated at whole plant stage under field condition with 7 dS m-1 soil EC, which three lines viz. MT41, MT189 and MT196 based on stress tolerance index (STI) were identified as salt tolerant mutants. However, regarding yield loss under salinity, three mutants viz. MT184, MT189 and MT196 were identified as salt tolerant lines. ISSR markers were used to assess genetic variability induced by mutation in mutant lines, which 50 percent of them detected polymorphism between wild cultivar and mutant lines. Cluster analysis using UPGMA method could classify studied genotypes into two distinct groups which mutant lines group showed over 2 times yield and stress tolerance index more than wild cultivar group. Based on this research, two mutant lines (MT189 and MT196) are introduced as salt tolerant lines at both seedling and whole plant stages. Also, it can be concluded that EMS-induced mutagenesis had a desire effect on the development of salt tolerant lines and that ISSR markers are applicable for differentiating salt tolerant mutants in rice mutant populations.