Genetic Analysis And QTL Mapping Of The Contents For Phytic Acid In Rice Grain

Phytic acid (PA) is the primary storage form of phosohorus (P) in cereal seeds; it chelates important minerals such as Ca2+,Mg2+,Zn2+,Fe3+,Mn2+ and virtually renders them indigestible by human and non-ruminant animals. Therefore, PA is commonly regarded as the major anti-nutritional component in cereal grains and can result in P pollution. Phytic acid accumulation difference at different position in rice,and generally the combining ability (GCA) effects and special combining ability effects were analyzed by complete diallel cross. Phytic acid accumulation was effected by N,P,K accumulation and metastasis at different organ and dynamic difference in different types of rice by using grouting period dynamic sampling method. F2 population was destructed by Zhonghua11 and LPA which there were great difference. Preliminary orientation QTL which controlled phytic acid content on chromosome linkage map, gene interaction effects was analyzed.The results were summaried as follows:1. Phytic acid contents in different parts of grain and rice quality traits were analyzed by using different types of rice. The average phytic acid contents in rice bran, brown rice, glume, and milled rice was 48.51, 9.77, 1.40 and 0.91 mg/g, respectively. Phytic acid contents in different parts of grain for different types of rice had a significant difference. The order of the phytic acid accumulation was as follows: rice bran>milled rice>glume. The phytic acid content in rice bran had a significantly positive correlation with those in brown rice and glume. The phytic acid contents in brown rice and rice bran both had significantly negative correlation with the protein content in rice, and significantly positive correlation with 1000-grain weight.2. In completely diallel hybridization population, PA was influenced by additive, non–additive effects and the cytoplasm effects, and mainly by additive effects. Generally the combining ability (GCA) effects was varied between varieties, Lengshuigu showed positive general combining ability effects, but Shennong265 showed negative general combining ability effects, both showed high significantly levels. Phytate content expression of F1 hybrid were not correlated with general combining ability effects, but was influenced by the special combining ability effects, was indicated that the performance and GCA effects for its parents could not be used to forecast the heterosis in hybrid rice. The crosses with larger specific combining ability effects did not exhibit high phytic acid content compared to their parents and were not correlated with crosses with good general combining ability effects. 3. The phytic acid contents between milk stage and maturity had a highly positive correlation trend of grain-filling in rice grain, phytic acid contents in maturity had positive correlation with N,P,K content in milk stage and maturity, and significantly positive correlation with N content in leaves in heading date and maturity, had significantly negatively correlation among N content in sheath in heading date, and K content in stem in milk stage, and P content in stem in maturity, and dry matter content in leaves , sheath, stem in filling stage.4. Phytic acid contents in rice and the important agronomic were continuously distributed as almost normally in F2, which were quantitative traits controlled by multiple genes.5. A molecular linkage map of 126 SSR and 4 STS markers was constructed, and covered a total length of 1522.9cM with an average distance of 11.71cM between adjacent markers in rice genome.6. Three QTL related to phytic acid content in rice seed were detected with Bayesian model selection. These located on chromosome 3, 5, 6, which explained 4.62%-8.02% of observed phenotypic variation, and the 2logBF variation is 3.6-5.23. The three positive alleles were from the parent"LPA". Six QTL for grain length and width was respectively located on chromosome 3, 5, 6, 7, 11, 12 and 1, 2, 5, 7, 8, 10, which respectively explained 1.16%-11.30%, 4.41%-10.89%, Three QTL for 1000-grain weight was located on chromosome 1, 3, 8, which explained 1.49%-12.45%.7. Ten pairs epistasis interaction effects effected phytic acid contents had been detected, which was located on chromosome 1, 3, 5, 6, 11, which explained 8.67%～24.73%. Interaction effects amplitude 1.69～5.18.