The Natural Selection Effect Of Part Characters In Soybean Recombinant Inbred Lines Derivated From Two Different Place

Soybean cyst nematode resistance and major agronomic traits are quantitative traits, and they are highly susceptible to environmental conditions, so it increased the difficulty of genetic research and breeding work. To improve the varieties on the adaptability of the ecological environment, it should strengthen the interaction of genotype and environment studies. In this paper,we analysed the natural selection effect on resistance to soybean cyst nematode resistance and agronomic traits from two levels of phenotypic and molecular, using two groups of recombinant inbred lines derived from the same hybrid combination, The results are as follows:1This study was based on the two populations "JN(RN)P7" and "NJ(RN)P7" which were recombinant inbred line (RIL) derived from Peking×7605at Jinan and Nanjing respectively. One hundred and forty-five SSR markers and one morphologic marker (BSC) which had polymorphism between parents were used to construct two genetic maps of soybean, which using Joinmap3.0sofeware. And eventually, we obtained two soybean genetic maps which contain27and25of the linkage groups respectively. The total length of two genetic maps were1574.80cM and1682.5cM. and the average distance between markers were separately13.58cM and15.72cM, For the population of JN (RN)P7, the range of each linkage group was17.3～127.4cM, at the other side for the population of NJ (RN)P7, the range of each linkage group was20.1～137.5cM.2Using the two recombinant inbred lines populations "JN(RN)P7" and "NJ(RN)P7" which derived from Peking×7605, and on the basis of the genetic linkage maps we constructed, QTLs of soybean cyst nematode resistance and two years of major agronomic traits were analyzed with software Windows QTL Cartographer V2.5. QTL results of soybean cyst nematode resistance showed that in JN(RN)P7population, we found2QTLs which located in A2and G linkage groups. At the same time a total of4QTLs were found in NJ(RN)P7population, which mapped in linkage groups A2、 Dlb、D2and O respectively. Results of Plant height、Branches、Nodes per plant、Pods per plant and100seeds weight in two years showed that, in2005, a total of13QTLs of JN(RN)P7population were detected in traits of Branches、Nodes per plant. Pods per plant and100seeds weight, which the genetic contributions of4QTLs were more than10%.In this population, we did not find QTLs related of Plant height. In NJ(RN)P7population, a total of23QTLs were found in five traits which were Plant height. Branches、Nodes per plant、Pods per plant and100seeds, the contributions of12QTLs were more than10%. In2009, a total of12QTLs of JN(RN)P7population were detected in the five traits,which the genetic contributions of4QTLs were more than10%. In NJ(RN)P7population, a total of23QTLs were found in traits of Plant height. Branches、Nodes per plant、Pods per plant and100seeds, the contributions of10QTLs were more than10%. In linkage groups G、C2and M of NJ(RN)P7population, we detdcted the same locis in two years, but in JN(RN)P7population, it had none.3In JN(RN)P7and NJ(RN)P7populations, we detected the gene frequency distributions of one hundred and forty-five SSR markers, compared the difference of gene frequency distributions in SSR markers、two genetic linkage maps and QTLs of two populations, the results showed that distributing frequency of49SSR markers were different between two populations, the structure of two maps had some diversity, and the results of QTLs in two populations also had large various. These results suggested that the genetic structure of two populations were different under the natural selection effect in various environment.