Mapping Of The Major QTL For Hundred Kernel Weight In Maize

Research on the mapping of major QTL for maize grain yield trait and its genetic mechanisms are becoming an effective way to get the high-yielding corn.Based on the preliminary findings,by using homozygous chromosome single segment substitution lines SSSL-Z22 as base material,which derived from the Chinese elite inbred lines Zheng58(receptor)and Chang7-2(donor),a sets of F2:3 families was derived from a cross of SSSL-Z22×Zheng58,and then a major QTL qhkw5-3 of hundred kernel weight traits was mapped.Based on the result of preliminary mapping,a population for fine mapping this major QTL which used backcross and MAS was developed.The main results obtained in this article were concluded as follows:301 F2:3 families from SSSL-Z22 × Zheng58 were the material,a major QTL qhkw5-3 of hundred kernel weight was located in Bin 5.06,flanked by the SSR markers mmc0481 and P9,its genetic distances is 8.8c M,which used target segment of the existing 6 SSR markers(P12-mmc0481-umc1680-phi087-P9-umc2201).In order to further narrow the interval,149 new SSR markers were developed,and 28 SSR makers(polymorphism between parents)were screened,and built a higher-density genetic map.The hundred kernel weight QTL qhkw5-3 was mapped in 8.8c M interval,flanked by the SSR markers SYM033 and SYM108.For further fine mapping the major QTL qhkw5-3 of hundred kernel weight,we developed a mapping population,which derived from a backcross of(SSSL-Z22×Zheng58)×SSSL-Z22.Based on the result of preliminary mapping,recombinations were screened in BC1F1 populations,which used SSR markers SYM033 and SYM108 flanked of qhkw5-3.In this study,14759 seeds were marker-assisted selection,1849 seeds of them were screen in target interval.Accelerating these seeds,seeds in the field.In order to obtain different length genotypes in target chromosome fragment,as much as possible,we screened reorganizations in different molecular markers locus,using seedling leaves extract DNA.Based on Molecular marker detection and genotype analysis,25 kinds of genotypes of recombinants,differet length of target chromosome fragment,were identified in this study.The results laid the foundation for the further fine mapping and cloning of the major QTL qhkw5-3 of hundred kernel weight in maize,also provided a reference for research on genetic mechanism of grain yield trait and molecular breeding of grain yield.