矮秆已被广泛用于改良作物的抗倒伏性状,培育理想株型,从而提高作物产量。玉米矮秆突变体K123d由自交系K123自然突变产生。本研究比较该突变体与野生型主要农艺性状差异及其对赤霉素的敏感性;用K123d与株高不同的3个自交系分别构建F1、BC和F2群体,分析矮秆性状的遗传模式;以K169/K123d-F2为定位群体,采用集团分离分析法(BSA),运用SSR标记定位矮秆基因d123;参照br-2序列信息分段设计特异引物,同源克隆d123。结果表明,与野生型相比K123d株高降低35.59%,穗位高降低、节间缩短、叶片较直立,但结实率差,对赤霉素敏感;在F2群体和BC1群体中,正常植株与矮秆植株分离比例分别符合3∶1和1∶1,说明矮秆性状受1对隐性基因控制;其矮秆基因d123定位于第一条染色体上SSR标记umc1278和bnlg1564之间,遗传距离分别为12.8 c M和7.3 c M;同源克隆显示d123与br-2存在12个碱基替换,其中第4个外显子编码的一个谷氨酸被替换为赖氨酸。由此可见,矮秆突变体K123d为br-2的一个突变类型,对矮化育种具有进一步研究利用价值。 Dwarf has been widely used to improve the lodging resistance of crops, cultivate the ideal plant type, thereby increasing crop yield. K123d, a maize dwarf mutant, was generated by a natural mutation of the K123 inbred line. In this study, we compared the main agronomic traits and their susceptibility to gibberellin between the mutant and the wild type. The F1, BC and F2 populations were constructed using three inbred lines with different K123d and plant height to analyze the inheritance of dwarf traits (D123) was constructed by K169 / K123d-F2. The d123 gene was cloned by group segregation analysis (BSA) and SSR marker was used to map d123. The specific primers were designed according to the sequence of br-2. The results showed that the height of K123d plants was 35.59% lower than that of the wild type plants, the ear height was decreased, the internodes shortened, and the leaves were erect but the seed setting rate was poor and sensitive to gibberellin. In F2 population and BC1 population, The dwarfing plants were separated by 3:1 and 1:1, respectively, indicating that the dwarfing trait was controlled by one pair of recessive genes. The d123 gene was located on the first chromosome between SSR markers umc1278 and bnlg1564, 12.8 cM and 7.3 cM respectively. Homologous clones showed 12 base substitutions between d123 and br-2, of which a glutamic acid encoded by the fourth exon was substituted with lysine. Thus, the dwarf mutant K123d is a mutation type of br-2, which has further research and utilization value for dwarf breeding.