Genetic Analysis Reveals a Major Effect QTL Associated with High Grain Zinc Content in Rice ( Oryza sativa L.)

Molecular mapping and application of quantitative trait loci (QTL) associated with a higher level of grain Zinc is aviable option to enhance zinc content in rice through breeding. An F2 population derived from a cross between a high yielding variety,BRRI dhan28, and a locally adapted Zn enriched cultivar, Kalobokri was used to map QTLs associated with higher levels of Zn in ricegrain. The F2:3 progenies varied significantly (P ＜ 0.0001) in Zinc contents with a mean value remarkably higher than those in thesuperior parent. Through marker by trait analysis using IciMapping, we detected a large-effect QTL, qGZn3 on chromosome 3 betweenRM5419 and RM1164 spanning 1.83 Mb interval at the 0.05 level of significance with a threshold LOD of 10.61. This QTL showed a21.1% (R2value) contribution to the total phenotypic variation for zinc content in the unpolished rice grains with 4.68 μg/g additiveeffect of Kalobokri alleles. We also detected 11 metal homeostasis related genes within the interval of qGZn3. In-silico analysis showedthat four expressed sequence tags of one candidate gene (LOC_Os03g22810) encoding Cu/Zn superoxide dismutase, a metal-bindingprotein, are highly active in the endosperm as well as in the embryonic tissue of rice grain. Taken together, our results suggest thatqGZn3 is a major QTL associated with high grain Zn content in the F2 progenies of rice. Our findings offer valuable genetic resourcesto facilitate breeding for high yielding and Zinc-enriched rice variety. KCI Citation Count: 0