水稻抗条纹叶枯病数量性状座位分析

为探明水稻品种窄叶青8号抗条纹叶枯病的数量性状座位，构建了窄叶青8号/武育粳3号F2群体的分子图谱，采用人工接种和田间自然接种两种鉴定方法，以病情指数比率为表型值，对每个F2单株衍生的F2∶3家系进行了抗条纹叶枯病鉴定。整个群体的病情指数比率均呈偏向于抗性亲本的连续性分布，表明条纹叶枯病抗性受数量性状基因的控制。进一步的QTL分析发现，两种鉴定方法所检测到的QTL完全不同，人工接种（强迫饲毒）方法仅检测到1个抗性基因位点qSTV7，其增强抗性的等位基因来源于窄叶青8号，而田间自然接种方法检测到2个抗性基因位点qSTV5和qSTV1，其增强抗性的等位基因分别来源于窄叶青8号和武育粳3号，暗示抗性亲本窄叶青8号可能携带耐病毒基因和抗灰飞虱基因，而感病亲本武育粳3号经遗传重组后，其抗性基因也得以表现。比较前人研究结果，发现检测到的QTL为新的抗条纹叶枯病基因位点，这些基因不同于抗条纹叶枯病主基因Stvb i，可为防止单一基因广泛使用造成的遗传脆弱性，提供新的抗性基因资源。

Analysis of Quantitative Trait Loci for Resistance to Stripe Disease in Rice

In order to verify the quantitative trait loci for the resistance to rice stripe in rice variety Zhaiyeqing 8, a molecular linkage map was constructed based on the F2 population derived from the cross of Zhaiyeqing 8 and Wuyujing 3. Reactions of the two parents, F1 individuals and 129 F2∶3 lines to the rice stripe were investigated by both artificial inoculation at laboratory and natural infection methods in the field attached the virus, and the ratio of disease rating index were scored. The ratios of disease rating index in Zhaiyeqing 8/Wuyujing 3 F2∶3 population ranged from 0 to 134.08 and from 6.25 to 133.6 by artificial inoculation at laboratory and natural infection methods, respectively, with marked bias towards resistant parent, Zhaiyeqing 8. This indicates the resistance to the rice stripe was controlled by quantitative trait loci (QTL). Further QTL analysis showed that the QTLs detected by two inoculation methods were completely different. Only one QTL, qSTV7,was detected by artificial inoculation, at which the Zhaiyeqing 8 allele enhanced the resistance to rice stripe, while the other two QTLs, qSTV5 and qSTV1, were detected by natural infection, and the resistant alleles came from Zhaiyeqing 8 and Wuyujing 3, respectively. These results showed that the resistant parent Zhaiyeqing 8 carried the genes associated with the resistance to the rice stripe virus and small brown planthopper, the resistant gene in Wuyujing 3 was expressed after recombination between Wuyujing 3 and Zhaiyeqing 8. In comparison with the results previously reported, QTLs detected in the study were new resistant genes to rice stripe. This will provide a new resistant resource for avoiding genetic vulnerability for single resistant gene, Stvb-i.