Genetic Research On Trace Minerals Content In Rice Seed

Today, micronutrient malnutrion has been one of most essential causes that are harmful to human health, resulting in egregious costs including lower effenciey of learning and work, higher morbidity and healthcare cost,excessive utilization of social resources and national economic resources. Strategy of plant breeding, especially the rice breeding of high mineral element contents in rice seed, is regarded as one of the most economical and sustainable approach which will overcome malnutrion of micronutrient. The study was based on F_2:3 population including 188 individuals and 43 lines, derived from a cross between two cultivars "Xiangheinuo 195 /Zhonghuazixiang nuo". Thegenetic variation and correlation coefficient and QTL mapping of Fe, Zn, Cu and Mn contents in rice seed were analyzed. The results were summaried as follows.Zn, Cu, Mn contents in rice seed were showed a continuous distribution near normal in F₂ population, which were quantitative traits controlled by multiple genes. While Fe content in rice seed were showed a continuous partial distribution, which were quantitative traits controlled by a few main genes.There existed significant or extremely significant positive correlations between Zn and Fe, Cu, Mn contents, Mn and Fe, Cu content, Fe and Cu content for F₂ population. However, Fe and Cu, Mn, Zn contents were not showed significant for F3 lines, Zn and Cu, Mn contents, Cu and Mn content were showed extremely significant positive correlations.A molecular linkage map of 132 SSR markers was constructed by using interval mapping, and covered a total length of 1928.5 cM with an average distance of 14.61 cM between adjacent markers in rice genome.14 QTLs related to Fe, Zn, Cu and Mn contents in rice seed were detected by using composite interval mapping. These QTLs included 7 QTLs for Fe content located on chromosome 1, 2, 7, 8, 11, which additive effect contribution rates varied from 4.41% to 17.63% and dominant effect contribution rates varied from 2.20% to 8.82% . 3 QTLs for Zn content were located on chromosome 4, 8, which additive effect contribution rates varied from 4.56% to 14.37% and dominant effect contribution rates varied from 5.38% to 9.19%.3 QTLs for Cu content were located on chromosome 8, 10, which additive effect contribution rates varied from 1.11% to 27.68% and dominant effect contribution rates varied from 2.21% to 35.43%.1 QTLs for Mn content were located on chromosome 8, which additive effect contribution rates was 16.77% and dominant effect contribution rates was 5.94%.Epistasis analysis of the F₂ populations showed 10, 5, 1 and 3 pairs of significant interaction sites, accounting for 52.83 %, 26.99 %, 6.83% and 39.98% of the total phenotypic variance respectively. Most detected epistasis belongs to additive / additive and dominant / dominant interaction effect, while a number of major QTL involved in the interactions.