Linkage mapping of QTLs for grain minerals (iron and zinc) and physio-morphological traits for development of mineral rich rice (Oryza sativa L.)

In the present investigation, experiments were conducted to evaluate F-3 and F-4 populations derived from cross between PAU201 (high-yield) and Palman 579 (iron-rich) indica rice varieties for various physio-morphological traits and minerals (iron and zinc) content. Phenotypic correlation analysis showed no correlation between grain iron and zinc content in F-3 and F-4 population (s). A DNA fingerprint database of 33 PAU201 x Palman 579 derived F-4 plants was prepared using 61 polymorphic SSR markers distributed on the entire genome of rice. The results of NTSYS-pc UPGMA tree cluster analysis and two and three dimensional principal component analysis (PCA) scaling showed scattering of the F-4 population between the two distinct parent genotypes; but more inclined towards Palman 579. The SSR data was used to identify quantitative trait loci (QTL) for grain mineral content and physio-morphological traits. A total of 128 alleles and three new recombinant alleles were identified in F-4 plants population. Composite interval mapping (CIM) analysis by WinQTL cartographer 2.5 revealed a total of six QTLs for mineral content (five for iron and one for zinc) in rice grains on chromosome 5, 6, 7, 9 and sixteen QTLs for various physio-morphological traits on chromosomes 2, 5, 7, 8, 9, 10 and 12. Linkage mapping of QTLs of minerals (iron and zinc) can greatly enhance the efficacy of breeding programs to improve mineral density in rice. The QTLs for minerals identified can successfully employed to improve the target traits through marker assisted selection.