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期 刊 ：植物遗传资源学报 2016年 17卷 4期

关键词：品种改良；稻瘟病抗性；分子标记辅助选择；抗谱；抗性水平；

Keywords:improvement of cultivar, blast resistance, marker-assisted selection, resistance spectrum, resistant level,

摘 要 ：稻瘟病是危害水稻产量的重要生物胁迫之一。实践证明，解决这一问题的最有效方法是培育具广谱、持久稻瘟病抗性的品种并推广种植。本研究以优质、高产、感稻瘟病的京粳1号为轮回亲本，与稻瘟病抗性基因Pi9、Pigm 和pi21的供体材料进行杂交、回交和复交，结合分子标记辅助选择和农艺性状筛选，培育不同的单基因导入系和聚合系。苗期人工接种多个稻瘟病菌的结果显示，Pi9抗性改良系的抗性频率达到100%，Pigm抗性改良系平均为90%，均极显著高于轮回亲本京粳1号的抗性频率，且农艺性状与京粳1号基本一致。pi21抗性改良系的抗性水平与京粳1号没有明显差异，单株产量极显著低于京粳1号。与轮回亲本相比，Pi9和pi21聚合系的抗性频率极显著提高，达到93.33%，但单株产量明显降低。研究结果证实了Pi9和Pigm基因在大幅度提高抗瘟性的同时对主要农艺性状影响小，都具有较大的育种利用价值。基因pi21抗谱较窄，抗性不强，且可能存在对产量的负效应，不宜单独用来改良水稻品种的稻瘟病抗性，需要与抗性强的主基因聚合，通过多次回交和自交打破该基因与产量的不利连锁累赘。

Abstract:Rice blast is one of critical factors that reduce rice production. Breeding and cultivation of cultivars with durable blast resistance and broad-spectrum has been proved to be the most promising strategy to solve this problem. To improve blast resistance of Jinggeng1, the introgression and pyramiding of blast resistance genes Pi9, Pigm, and pi21 were conducted through crossing, backcrossing, multiple crossing and self-crossing in combination with marker-assisted selection (MAS) and selection against agronomic traits. The results showed that resistance frequency of the resistance-improved line with Pi9 reached 100%, and that of the resistance-improved lines with Pigm averagely reached 90%. Both of them were extremely significantly higher than that of recurrent parent Jinggeng1. And the agronomic traits of these lines were quite similar with that of Jinggeng1. The resistance-improved line with pi21 had no significant difference of resistance frequency with Jinggeng1 but had significantly decreased grain yield per plant as compared with Jinggeng1. Comparing with Jingjing1, the resistance frequency of pyramiding line of Pi9 and pi21 was significantly improved, reaching 93.33% with significant decrease in grain yield per plant. The results indicated that introgressions of Pi9 and Pigm can greatly improve blast resistance and have less negative effects on agronomic traits, thus showing great potential application of the two genes in rice breeding for blast resistance. Due to pi21‘s relative poor resistance and narrow resistance-spectrum as well as possible negative effects on yield, it isn’t recommended to separately use it for improvement of blast resistance. Combination of pi21 with other strong resistance genes could be proper for improvement of blast resistance by multiple backcross and selfing to break its unfavorable linkage drag with yield trait.

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