| Resistant starch (RS) is a kind of starch and its degradation can not be absorbed by the small intestine of healthy people, it has lower postprandial glycemic number, can improve mineral absorption capacity of the body, improve intestinal flora balance,has anti-cancer pHysiological effect and so on, RS is a new type of dietary fiber. Rice is the main source of nutrition and energy for our country people, cultivating a high resistant starch rice can improve the unbalanced nutrition status of people. In this experiment, the selection of high resistant starch rice germplasm resources and genetic localization are conducted, aiming to develop the Ningxia local high resistant starch content rice resources and provide theoretical basis for breeding high resistant starch rice resources.Our research measured the resistant starch content of 88 germplasm resources in Ning Xia and discussed the differences between them, explored the relationships between resistant starch content and grain shape, built the the F2 group of "NingJing 28/Jiang Tangdao",the two parents have significant differences in RS content,analyzed the resistant starch content genetically.And use the F2 populations to construct genetic linkage map using interval mapping method to locate the QTLs that control rice resistant starch content.The main results are as follows:1.In this experiment, RS content of 88 rice germplasm resources are measured,the results showed that:Resistant starch content of brown rice resources measured is in the range of 2.14%-13.79%, with an average of 4.06%,showing a higher coefficient variation of 46.06%.RS content of both Ningxia local rice varieties and non-local has a high coefficient of variation,T test shows they has no significant differences.2.Three high RS rice varieties are selected from 88 germplasm resources,they are Jiang Tangdao,Ning Nongheijing and Aoyu 326,the RS contents of them were 13.72%,12.07% and 11.94%,3 to 6 times the normal rice varieties3.RS content of brown rice resistant starch content has no significant relationship with grain length, grain width, grain weight, and the length/width of grain.However,short grain always has lower RS content.4.Genetic analysis of RS content of the F2 population of parent group "Ningjing 28/Jiang Tangdao" showed that:F2 maximum is 20.42%, the minimum is 1.22%, RS content of two parents were 2.61% and 13.72%,RS content may show transgressive segregation and has heterosis, frequency lower than the lower parent is higher than the frequency higher than the higher parent.F2 average is 4.85%, close to the lower parent,means RS content is more low-parent inherited.The major frequency curve of RS content of the F2 plants is single-peaked and positive according with inheritance of quantitative character controlled by polygenes.5.With 171 polymorpHic primer pairs screened from 1276 pairs of primers of the parent group "Ningjing 28/ Jiang Tangdao",123 SSR pairs are selected to draw a genetic linkage map with Map chart 2.2 software, the total length of the genetic map is 1397.3cM, the average map distance between markers is 11.36cM.6.QTL mapping analysis of rice RS content of F2 populations showed that 8 QTLs are related with rice RS content, located on chromosome 2,5,6,10,11,12,contribution rate lies in the range of 3% to 16%. Among witch has two main effect QTLs, qRS-5-1 located on the RM17793-RM3328 sector of chromosome 5 and qRS-10 located on the RM3373-RM269 sector of chromosome 10, can respectively explain 13% and 16% of RS variation, QTL detection results illustrate that the RS inheritance of brown rice is different from the inheritance of white rice,it is a quantitative trait controlled by a few major genes and many minor genes. |
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