Association Mapping For Several Mineral Elements In Brown Rice

The development of social economy is boosting demands for better quality rice. As one of important parameters for nutritional quality, rice mineral elements have received more attention by an increasing number of people. About 60% of the world people suffer from micro-elements deficiency, sub-health and many diseases attribute to the lack of mineral elements. Rice is the staple food of more than 50% of the world’s population, it is of great significance to explore and enrich the micro-elements of rice varieties to improve human health. In this study, the genetic diversity of different mineral elements in rice grains was analyzed by two sets of rice germplasm resources. The main results are summarized as follow:1. The genetic diversity in Fe, Zn, Se, Pb and Cd in an association panel consisting of 378 rice accessions was investigated. Among seven subpopulations, the mean values of Zn and Cd in the japonica group were significantly higher than in the other six groups in the indica background. The population structure accounted for from 5.7%(Se) to 22.1%(Pb) of the total variation. Correlation analyses showed that there was a significantly positive correlation between Fe and Zn (P< 0.001), but no close correlations were found between Se and Fe or Zn content. Pb was positively correlated with the other minerals (P< 0.001) except for Se.20 QTLs associated with the five minerals (Fe, Zn, Se, Pb and Cd), including some previously reported and new candidate loci, were identified by association analysis. Particularly, three cases of QTL colocalization, i.e.Cd and Pb on chromosome 5, Zn and Pb on chromosome 7, and Se and Pb on chromosome 11, were observed.2. The genotype x environment interaction for the Mg, Na, K, Ca, Zn and Cu content in 20 re-sequencing rice materials provided by International Rice Research Institute was investigated. Analysis of variance showed that the Ca, Na and K content were mainly affected by the genotypic variance, whereas the Fe, Zn and Cu content were mainly affected by the environment variance. The genotype X environment interaction effects for Mg, Na, Zn, and Cu were highly significant (P< 0.001). The results of pair-wise correlation analysis showed that the content of Mg, K, Zn was positively correlated with the content of other minerals. The content of Cu was negatively correlated with the content of Na and K and positively correlated with the content of other minerals. The correlation between Ca and the other minerals was not significant. Preliminary association test found that 17 loci were strongly associated with the five minerals (Ca, Cu, K, Na and Zn), which were located on chromosome 1,2,6,8,10 and 11.