水稻半矮秆多分蘖突变体w271的表型分析与基因定位OA

To enrich the theory of rice(Oryza sativa L.)plant type breeding and utilize the excellent dwarf germplasm resources,using the high-quality rice variety Dalixiang as the material,EMS methylsulfate was used for mutagenesis to obtain a stable and heritable semi-dwarf multi-branched mutant w271.Through phe-notypic analysis and gene mapping,its application potential in breeding was clarified.The results showed that compared with the wild type,the height of w271 decreased by one-third,the effective tillers increased by 6 and the theoretical yield per plant increased significantly.It also exhibited characteristics such as thicker stems,earlier heading time,thicker grains and increased seed set rate.Genetic analysis indicated that the semi-dwarf phenotype of mutant w271 was regulated by a single recessive nuclear gene.The F1 generation was obtained by crossing w271 with the high-stalk indica rice variety Fanhaopi,and the F2 generation segre-gation population was obtained by selfing.The mutant gene of w271 was located at the end of the long arm of chromosome 1 by bulked segregation analysis(BSA).The semi-dwarf gene SD1 in the defined interval revealed 383 base pair deletions and 1 A base insertion,resulting in a frameshift mutation and premature translation termination.After overexpression of the wild-type SD1 gene in the w271 mutant,the plants became taller.Therefore,the mutant phenotype of w271 was caused by the variation of the SD1 gene and SD1 could be an important molecular target for the improvement of the plant type of Dalixiang.