Indica rice line 75-1-127 carrying broad-spectrum rice blast resistance gene Pi9 was used as resistance gene donor for genetic improvement of Yangdao 6 and R6547.By alignment of genomic sequences from the Pi9 locus of 75-1-127, Yangdao 6 and Nipponbare, co-dominant STS (sequence-tagged site) marker PB9-1, which linked to the Pi9 gene, was developed for molecular marker-assisted selection (MAS).Eight backcross lines carrying Pi9 were obtained, among which four lines contained the genetic background of Yangdao 6 and the other four lines had the R6547 background.Under natural disease infection conditions in Enshi County and Yichang County of Hubei Province, China, the Pi9-carrying lines showed higher blast disease resistance than Yangdao 6 and R6547 in various degrees.The hybrids originated from 08C893, an R6547-derived rice line, showed higher blast disease resistance as compared to the control Yangliangyou 6.The results suggest PB9-1 is an effective codominant marker for MAS of Pi9 which is a valuable resistance gene for the control of rice blast disease in Hubei area.%利用带有广谱抗稻瘟病基因Pi9的籼稻品系75-1-127作为抗病基因供体亲本,用于扬稻6号和R6547抗病性的回交育种.通过比较75-1-127、扬稻6号和日本晴的Pi9基因位点的DNA序列,开发出了与Pi9基因紧密连锁的共显性STS(序列标记位点)标记PB9-1,用于Pi9基因的分子标记辅助选择.结合田间农艺性状选择和分子标记辅助选择,培育出8个Pi9基因纯合的回交后代株系.其中,具有扬稻6号和R6547遗传背景的株系各4个.经湖北恩施和宜昌的病圃鉴定,携带有抗病基因株系的稻瘟病抗性水平较受体品种扬稻6号和R6547有不同程度的提高.具有R6547遗传背景的株系08C893配制的杂交组合在上述病区的抗性表现也明显优于对照品种扬两优6号.上述结果说明,共显性标记PB9-1在Pi9抗稻瘟病基因分子标记辅助育种中具有应用价值,并且Pi9基因作为稻瘟病抗源之一可以在湖北稻区进行有效利用.
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