Mapping Of The QTL For Grain Size And Related Traits In Maize

Research on the mapping of major QTL for maize grain yield-relatedtraits and their genetic mechanisms are becoming an effective way to get thehigh-yielding corn. Now, the chromosome single segment substitution lines (SSSL) isconsidered to be the ideal material for study on complex trait QTL detection, finemapping and gene cloning.Based on the preliminary findings, this study used single segment substitutionlines SSSL-Z22which derived from donor strain Chang7-2in the genetic backgroundof the recipient Zheng58strain as the experimental material, the substitution segmentis bnlg1847… umc1680… bnlg1306. Constructed the F2:3group and secondaryseparation population from SSSL-Z22×Zheng58, and mapped the QTL for100-kernel weight and related traits in maize through the methods of winQTLcart2.5and overlap mapping. The main results obtained in this article were concluded asfollows:231F2:3families from SSSL-Z22×Zheng58were the material, exploited newmolecular markers, built a high-density genetic map with SSR markers in the targetchromosome regions, the100-kernel weight QTL q100kw-5-3was located in Bin5.06,flanked by the SSR markers P12and umc2306, whose genetic distances is9.2cM.Linkage analysis showed that a grain width QTL was navigated between the SSR markers P12and umc2306, and the confidence interval of grain width QTL qgw-5-3was the same as the100-kernel weight QTL. In mapping groups, the correlationcoefficient of100-kernel weight with grain length, grain width and grain thicknesswere0.619**、0.674**、0.079, respectively. Results showed that the100-kernelweight decreased of single segment substitution lines SSSL-Z22was mainly due tothe grain width narrowed.Through the overlap mapping analysis secondary separation population fromSSSL-Z22×Zheng58, the100-kernel weight QTL q100kw-5-3and grain width QTLqgw-5-3were positioned in the Bin5.06, flanked by the SSR markers umc1680andphi087, the distance between the two markers was0.9cM.The results laid the foundation for the further fine mapping cloning of grain sizerelated trait gene in maize, also provided a reference for research on geneticmechanism of grain yield related traits and molecular breeding of grain yield.