分子标记辅助选择改良水稻两用核不育系创5S稻瘟病抗性和镉积累特性研究

Improvement of Blast Resistance and Low Cadmium Accumulation of Dual-purpose Genic Male Sterile Rice Line Chuang 5S by Molecular Marker-assisted Selection

为了培育抗稻瘟病且籽粒镉低积累的水稻两用核不育系,利用谷梅4号、天津野生稻和魔王谷为稻瘟病抗源,Cd14030(日本晴的衍生系)为稻米镉低积累基因OsHMA3的供体亲本,采用分子标记辅助选择技术和逐步聚合的方法,创制了基于创5S(C5S)背景的包含抗病双基因和镉低积累基因的三基因聚合系。三基因聚合系的苗瘟感病级别为1.5~2.1级,与抗病双基因聚合系无显著差异,但三基因聚合改良株系的糙米镉含量因亲本来源而异,其中,基因型为C5S(Pi49+Pigm+OsHMA3)的改良系糙米镉含量为0.051~0.067 mg/kg,与日本晴(0.051 mg/kg)相当,较C5S(0.118mg/kg)下降43.2%~56.8%,较好地将稻瘟病抗性与镉低积累特性聚合于两用核不育系创5S中。此外,三基因聚合改良株系的主要农艺性状大多与C5S相近,其中有一些株系甚至在每穗总粒数与一次枝梗数上还得到了改良。

To develop the dual-purpose genic male sterile rice lines with both low grain cadmium accumulation and blast resistance,the improved three-gene polymerized lines of Chuang 5S(C5S),containing two blast resistance genes and a low cadmium accumulation gene,were successfully developed with Gumei 4(Pigm),Tianjinyeshengdao(Pi2-1)and Mowanggu(Pi49)as blast resistance sources and Cd14030(a derivative of Nipponbare)as the donor parent of the low cadmium accumulation gene OsHMA3,through the molecular marker-assisted selection(MAS)technology and the progressive aggregation method.The field identification of rice seedling blast resistance showed that the disease score of the three-gene polymerized lines,namely C5S(Pi49+Pigm+OsHMA3)and C5 S(Pi49+Pi2-1+OsHMA3),were1.5~2.1,not significantly different from those of the two-gene polymerized lines,namely C5 S(Pi49+Pigm)and C5 S(Pi49+Pi2-1).However,the grain cadmium content of three-gene polymerized lines varied with the donor parents of rice blast resistance gene.Among them,the grain cadmium content of the three-gene polymerized lines with the genotype of C5 S(Pi49+Pigm+OsHMA3)was 0.051~0.067 mg/kg,close to that of Nipponbare(the source of low cadmium accumulation,0.051 mg/kg)but 43.2%~56.8%lower than that of C5 S(the recipient parent,0.118 mg/kg),indicating the integration of both blast resistance and low grain cadmium accumulation into the dual-purpose genic male sterile rice line C5 S.In addition,the main agronomic traits of the improved three-gene polymerized lines were mostly similar to C5 S,and some of them were even improved in the traits of the number of spikelets per panicle and the number of primary branches.