分子标记辅助选择改良杂交水稻Q优6号的稻瘟病抗性

Improvement of Rice Blast Resistance of Hybrid Rice Q You 6 by Molecular Marker-Assisted Selection

为了提高长江中下游稻区大面积推广的中熟三系杂交中稻组合Q优6号的稻瘟病抗性,采用杂交、回交和分子标记辅助选择技术,将抗稻瘟病亲本材料75-1-127的广谱抗性基因Pi9渗入到Q优6号的父本R1005中,通过Pi9基因分子标记选择和综合农艺性状选择,育成了3个携带Pi9基因的株系CY11705-38、CY11707-6和CY11708-15,并与Q优6号的母本Q2A配制了3个组合。经主要农艺性状、产量、稻米品质分析和稻瘟病病区抗性鉴定,CY11705-38和CY11707-6的主要农艺性状、产量、稻米品质与R1005相似,稻瘟病抗性明显提高;组合Q2A/CY11705-38和Q2A/CY11707-6的主要农艺性状、产量、稻米品质与Q优6号相似,稻瘟病抗性也明显提高。认为以Q2A/CY11705-38或Q2A/CY11707-6替代Q优6号,可以在保持产量、生育期、稻米品质和主要农艺性状相似的基础上,明显提高稻瘟病抗性,降低生产风险。

Q You 6, a widely-used three-line hybrid rice combination for single cropping rice area in middle and lower reaches of Yangtze River Valley, is susceptible to rice blast resulting in yield losses. The blast resistance gene Pi9 from 75-1-127 was transfered into the male parent R1005 of Q You 6 by molecular marker assisted selec- tion and backcrossing. Three improved lines （CYl1705-38, CY11707-6 and CYl1708-15 ） carrying Pi9 gene with the genetic background of R1005 were developed and crossed with Q2A, the female parent of Q You 6. The resuhs of blast evaluation at Enshi and Yichang, the rice blast prevalent areas in Hubei Province, showed that three lines and their derived hybrids were resistant to blast. The evaluation results of yield, main agronomic traits and grain quality traits showed that CYl1705-38 and CYl1707-6 and their derived hybrids were similar to the recipient R1005 and Q You 6, respectively. Therefore, it is recommended that Q2A/CY11705-38 or Q2A/CY11707-6 sub- stitute for Q You 6 in rice production, which will improve the blast resistance and reduce the production risk with- out changing the grain yield, growth duration and grain quality and other major agronomic traits of Q You 6.