Linkage Mapping for Grain Iron and Zinc Content in F2 Population Derived from the Cross between PAU201 and Palman 579 in Rice (Oryza sativa L.)

Molecular markers provide novel tools for linkage mapping of QTLs of target traits and can greatly enhance the efficacy of breeding programs to improve mineral (iron and zinc) density in rice. A F-2 population derived from the cross between high-yielding (PAU201) and iron-rich (Palman 579) indica rice varieties displayed large variation for various physio-morphological traits including grain yield per plant and iron and zinc contents. Transgressive segregation for grain iron and/or zinc contents was noticed in some F2 individuals with one of the F2 plants having exceptionally higher iron (475.4 mu g/g) as well as zinc (157.4 mu g/g) contents. Grain iron content showed significant positive correlation (r = 0.523) with grain zinc content indicating the feasibility of improving iron and zinc levels simultaneously in rice grain. Two parental rice varieties displayed polymorphism at 76 of the 100 SSR loci, which were used to map the QTLs associated with mineral content in grains. Composite interval mapping (CIM) analysis by Win QTL cartographer 2.5 revealed a total of eleven QTLs for mineral content (eight for Fe and three for Zn) in rice grains on chromosomes 2, 3, 7, 10 and 12.