基于残余杂合系的水稻显性矮秆基因的定位及KASP标记开发

Mapping of Dominant Dwarf Gene based on Residual Heterozygous Lines and Development of KASP Markers

株高是和水稻高产、稳产密切相关的重要农艺性状,发掘可育种利用的矮秆基因有重要的应用价值。本研究利用育种残余杂合系,鉴定了一个显性矮秆基因sd9,该基因能将株高降低18 cm。近等基因系F群体的遗传学分析显示矮秆植株与高秆植株的分离比为3:1,表明sd9为显性矮秆基因。构建了极高单株和极矮单株两个极端表型DNA混合池。利用靶向测序基因型检测(genotyping by target sequencing, GBTS)和40 k水稻SNP检测液相芯片相结合的方法进行了DNA混合池的基因型鉴定,将sd9基因定位于第9染色体14 976 197~14 993 586 bp区间。根据该区间的SNP开发了sd9连锁的KASP标记,验证了定位结果。分子标记的单因素方差分析显示:区间内的分子标记和株高极显著相关。单个标记QTL检测LOD值为57.50,解释表型效应66.50%。利用育种残余杂合系鉴定的sd9及其KASP标记的开发,可以为水稻株型的分子育种提供可直接利用的基因资源。

Plant height is an important agronomic trait closely related to high and stable rice yield.It is of great application value to discover dwarf genes that can be used for breeding.In this study,a dominant dwarf gene sd9,was identified using the breeding residual heterozygous line,which reduced plant height by 18 cm.Genetic analy-sis of the near-isogenic F_(2) population showed that the segregation ratio of dwarf plants to tall plants was 3:1,indicating that sd9 was a dominant dwarf gene.Two extreme phenotypic DNA pools were constructed,the extremely high in dividual plant and the extremely short individual plant.The genotype identification of the DNA mixed pool was carried out using genotyping by target sequencing(GBTS)method with 40 k rice SNP detection panel,and the sd9 gene was located in interval 14976197〜14993586 bp on chromosome 9.KASP markers was developed based on SNPs in this interval,and the mapping results were verified.One-way ANOVA of molecular markers showed that the molecular markers in the interval were significantly correlated with plant height.The LOD value of single marker was 57.50,explaining 66.50% of the phenotypic effect.The development of sd9 and its KASP marker identified by breeding residual heterozygous lines can provide directly usable genetic resources for molecular breeding of rice.