Ghd7 is a negative regulator of zinc concentration in brown rice

Zinc (Zn) is an essential micronutrient for human, and improving Zn concentration in rice could be a simple and effective way to solve insufficient Zn uptake from daily diet. In this study, a recombinant inbred line (RIL) population was developed from a commercial hybrid combination Wandao153, and subjected to quantitative trait loci (QTL) detection for Zn concentration in brown rice and heading date. Five QTL for Zn concentration and six for heading date were detected across 2 years, among which two QTL for Zn concentration and two for heading date were co-located on chromosome 7 and 8, respectively. The two co-located QTL on chromosome 7, qZn7 and qHd7, were likely to be Ghd7, a major gene for heading date and yield potential in rice. A combination of Zn concentration analysis and haplotype analysis of three pairs of genetic materials for Ghd7 revealed that it is a negative regulator of Zn concentration in brown rice. The other two co-located QTL on chromosome 8, qZn8 and qHd8, were likely to be Ghd8/DTH8, another major gene for heading date and yield potential in rice. These results could be of great use in genetic improvement of Zn concentration in brown rice.