Identification and Validation of Putative Candidate Gene Markers For Grain Iron Content in Recombinant Inbred Lines of Rice (Oryza sativa.L)

Genetic variability studies and molecular level understanding of Fe translocation and homeostasis paved the way for combining the desirable grain characters of improved varieties with high iron content in grains. The objectives of the experiment were to evaluate grain Fe concentration and candidate gene markers associated with this trait among 160 recombinant inbred lines population derived from a cross between IRRI 38 and Jeerige sanna, of rice and validate the putative markers in another biparental RILs mapping population. Grain iron concentration in RILs ranged from 7.20 ppm to 24.00 ppm with an average of 11.30 ppm. Out of 41 candidate gene markers, 11 showed polymorphism between parents. It included 8 putative candidate gene markers, 2 candidate gene based SSR primers and one SSR marker. Single marker analysis of 11 polymorphic markers on RILs mapping population showed that four gene specific markers viz.OsNRAMP5g, OsMTP1a, OsYSL4e and OsZIP8a and one candidate gene based SSR primer; iRMm9-1 is associated with grain Fe concentration. Validation of these markers on 69 segregants of another mapping population showed that only two markers OsYSL4e and OsZIP8a are significantly associated with grain Fe concentration with phenotypic variance of 11.9% and 9.2% respectively. Thus the high priority candidate genes for high Fe in grains identified in this study are OsYSL4 and OsZIP8 located on 5 and 7 chromosomes respectively.