Analysis of QTL responsible for grain iron and zinc content in doubled haploid lines of rice (Oryza sativa) derived from an intra-japonica cross

Quantitative trait loci (QTL) related to the grain iron and zinc contents of brown rice were mapped by using a doubled haploid population derived from an intra-japonica cross between 'Hwaseonchal' and 'Goami 2'. QTL-QTL, background-QTL, and background-background interactions and candidate genes that affect grain iron and zinc contents were preliminarily identified. Twenty-one iron- and zinc-related QTL were found. The major-effect QTL qFe7 and qZn7 provided the highest contribution to phenotypic variance for grain iron and zinc contents. The colocation of zinc- and iron-related QTL on chromosomes 1, 4, 7 and 11 may account for the strong correlation between iron and zinc contents. A region on chromosome 7 and epistatic interaction between loci on chromosomes 2 and 10 affected iron content. qZn7 and qZn11.3 exerted additive effects on zinc content. Eleven iron- and zinc-related candidate genes colocated with qFe7, qZn7 and the region on chromosome 7 with an additive effect on iron content. The major-effect QTL identified here may be useful for breeding biofortified rice.