Genetic Analysis And QTL Mapping Of Resistant Starch Content In Rice Grain

The inheritance of the grain resistant starch content was investigated by a6²diallel design and6combinations’ reciprocal cross in order to obtain the rice hybridswith high resistant starch content. F₂and F₄population were destructed byJiangtangdao1and Miyang23which there were great difference in resistant starchcontent. Preliminary and fine orientation QTL which controlled rice resistant starchcontent on chromosome linkage map.The main research results were summarized asfollows:1. The general combining ability（GCA） of parents and special combiningability（SCA） of F₁hybrid were analyzed by variance analysis through Griffing ModelⅡ. Resistant starch content was affected by additive, non-additive effects and thecytoplasm effect, and mainly by additive effects. GCA effects were obviousdifference between the parents.‘Jiangtangdao1’ and ‘Bing9331’ showed high positivegeneral combining ability effects, and the general combining ability effect valueswere0.303and0.101respectively. The others showed negative general combiningability effects. While the others showed negative general combining ability （GCA）effects. The expression of F₁hybrid resistant starch content was not significantlycorrelated with GCA effects,but was affected by the SCA effects, indicated that theselection of high resistant starch content of rice should be focused on screening andidentification of genotypes basing on screening of parental quality. And the riceresistant starch content heterosis depended on SCA effects.2. The parental value was not significantly correlated with SCA effects, but wassignificantly correlated with GCA effects, indicated that the expression of parentalresistant starch content had the similar trend with GCA. The expression of F1resistantstarch content had significantly positive correlation with SCA effects and parental values, but was not significantly correlated with parental GCA effects. SCA effectswere acquired after combination. So the parental value could be used to forecast theheterosis in F1hybrid rice.3. A molecular linkage map of88SSR markers was constructed, using MapQTLprogram, and covered a total length of1213.5cM with an average distance of13.8cMbetween adjacent markers in rice genome.4. Only one major QTL on chromosome2was identified between RM6611andRM13366. Genetic distance of the interval was11.7cM, the physical distance was2.2Mb. The LOD value was36. The major QTL explained60.4%of total variation inthe F2population for RS with additive effect of-3.2259and dominant effect of-3.1314, indicated that the positive alleles were from Jiangtangdao1of high resistantstarch content.5. Using656plants from four F_3:4families and new molecular markers, targetinterval was fine mapped to a573.3Kb region between InDel2and InDel6...