【摘要】 本研究利用一个广谱抗稻瘟病基因d12(来源于武育粳2号),通过分子标记辅助选择改良珍汕97B抗稻瘟病性。首先利用以珍汕97B为背景构建一个包含236个单株的d12近等基因系BC2F2群体,通过遗传分析,将抗稻瘟病基因d12定位于水稻第12染色体的遗传距离为2.7cM的2个SSR标记RM27792-RM28089之间。QTL分析结果表明,在分蘖期Ⅰ(TL58,播种后第58天考察的叶瘟)和分蘖期Ⅱ(TL75,播种后第75天考察的叶瘟)检测到的d12的LOD值和VAR值(遗传方差/表型方差)分别为:31.7、47.1%以及24.1、37.9%,d12的加性效应和显性效应分别为1.2608、-1.0475以及0.7326、-0.7689;当水稻进入抽穗期(HL98,播种后第98天考察的叶瘟)时,检测不到d12。由此可见,d12对稻瘟病抗性随着水稻的分蘖进程可能由强到弱,当进入生殖生长时期对稻瘟病的抗性没有了贡献。这可以表明d12对稻瘟病的抗性受到发育时期的影响。以上结果可能对稻瘟病持久抗性的育种和受发育影响的抗病性的理解有非常重要的意义。更多还原

【Abstract】 Zhenshan 97B is a maintainer lines widely used in hybrid rice production in China. However, Zhenshan 97B is very susceptible to rice blast, Magnaporthe grisea, resulting in a limit of its use in rice production. The objective of this study was to improve the blast resistance of Zhenshan 97B by introgressing d12, a broad-spectrum blast resistance gene (from a resistant rice cultivar Wuyujing-2), into Zhenshan 97B through molecular marker-assisted selection (MAS). The use of a BC2F2 near isogenic line in the Zhenshan97B background allowed us to analyze d12 on chromosome 12. At two different time points of tillering stage, d12 contributed differently to the total variation of leaf blast resistance in this BC2F2 population, 47.1% for TL58 (leaf blast resistance 58 days after germination at tillering stage, TL58) with LOD=31.7 and 37.9% for TL75 (leaf blast resistance 75 days after germination at tillering stage, TL75) with LOD=24.1, respectively. The addictive effect and dominance effect of d12 are 1.260 8, -1.047 5 for TL58 and 0.732 6, -0.768 9 for TL75. No effect of d12 was detected on leaf blast resistance at heading stage for HL98 (leaf blast resistance 98 days after germination at heading stage, HL98). The decreasing effects of d12 on rice blast throughout the life cycle of rice suggested that d12 was a development-related resistance gene. Our results might have important implications for durable resistance breeding and improve our understanding in development-related disease resistance genes in plants.更多还原