Selection Of Enriched Zinc Content Of Rice Germplasm Resources And Genetic Analyses And QTL Mapping For Zinc Content In Rice Grains

Rice is first major grain crops in China and it has become the hot topics for the nutrition research of trace elements in the functional rice.Zinc is one of the indispensable trace elements in organisms,it plays an important role in growth development and physiological metabolism for plants and animals.Moreover zinc is one of the most failing trace elements in human body,especially for children and pregnant women. Therefore, increasing the zinc contents in rice by breeding method has a great significance for improving people’s zinc deficiency.This study aimed at providing certain theoretical basis for developing functional rice of enriched zinc rice through selection of enriched zinc content in rice gennplasm resources and genetic analyses and QTL mapping for zinc content in rice grains.This experiment determined the zinc contents of 102 rice gennplasm resources to select enriched zinc content rice gennplasm, and analyzed the rice grain zinc content and the correlation of grain shape, iron content and other traits. It is built a F2 population which enriched zinc content rice variety "Ningda-62" with low zinc content rice variety "Ningjing-40".and make genetic analysis for its posterity grain zinc content; The linkage map was constructed used the F2 segregation population and conducted QTL mapping for grain zinc content adopted for Interval mapping. The main results were as follows:1. The grain zinc content of 102 of rice germplasm resources in Ningxia was determined used atomic absorption spectrometry. The results show that rice grain zinc content have obvious difference between different genotypes. The average value of grain zinc content is 19.51 mg/kg and the variation range is 12.75-36.00 mg/kg in 102 rice germplasm resources. Some enriched zinc content rice varieties were selected such as "Yanghebaipidao","Changguidao-5","Dalidao", "Ningda-62" and low zinc content rice varieties "Jijing-44"、"Ningjing-35"、"Xiaolinuo"2. The average value of grain zinc content is 20.12 mg/kg and the variation range is 14.58～36.00 mg/kg in 24 Ningxia local varieties. The average value of grain zinc content is 19.32mg/kg and the variation range is 12.75～29.50 mg/kg in 78 outland rice varieties. The zinc content of local rice varieties have a bigger variation range and a higher average content than the outland rice varieties. Using variance analysis for the zinc content between local rice varieties and outland rice varieties,the result shows that there is no significant difference between the two.3. The grains zinc contents of 102 rice gennplasm resources in Ningxia have a very significant positive correlation with grain length, the correlation coefficient is 0.382.It is a significant positive correlation with the aspect ratio,and a positive correlation with grain width and 1000 grain weight.a negative correlation with grain thick. Zinc contents and iron contents in grains existed significant positive correlation.4. The Genetic analysis of grain zinc content in which the hybrids "Ningda-62/Ningjing-40"F2 generation shows that the grain zinc contents in two parents "Ningda-62" and"Ningjing-40" is 27mg/kg and 18.5mg/kg. The grain zinc contents in F1 generations is 20.32 mg/kg. The average value of 190 F2 plants is 18.97mg/kg, which is between two parents and trended the low zinc content parent "Ningjing-40",the variation range is 15-26mg/kg. F2 population plants’grain zinc contents is consequent left skewed positively distribution which can be concluded that the rice grain zinc content is influenced by quantitative trait controlled by multiple genes.5. From 1050 pairs of SSR primers,152 pairs polymorphic primers were screened. As the F2 population "Ningda-62/Ningjing-40", a genetic linkage mapping was constructed which contained 130 markers,covering the rice genome 1682.7cM and the average distance between markers was 12.94cM.6. This study analysis rice grain zinc contents of F2 populations for QTL mapping. The result shows there are 6 QTLs related to grain zinc contents. They are located on chromosome 2,4,6,9,12 and the range of contribution rate is 7%～13%. The QTL locus "qZn-6" in 6th chromosome is maximum contribution rate at 13%.6 QTLs locus additive effects are all positive value, synergistic alleles are from high zinc contents parent.