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水稻黑条矮缩病是由灰飞虱传播的一种病毒病,最近在江苏、浙江等省暴发给水稻生产造成严重威胁。本研究在前期对水稻黑条矮缩病抗性基因初步定位的基础上,针对第6染色体短臂上紧密连锁的2个抗性QTL,以抗性亲本“明恢63”为供体,感病亲本“淮稻5号”为轮回亲本,通过标记辅助选择,构建了携带目标抗性QTL的系列近等基因系。自然接种和人工接种鉴定表明新培育的近等基因系其发病率较对照轮回亲本下降25%左右,抗性得到显著改良。农艺性状调查结果显示大多数近等基因系其生育期、株高及产量构成性状等与轮回亲本相似,表明目标区段存在较少的累赘连锁。此外,对有关如何实现目标QTL的精细定位,以及利用标记辅助选择聚合多个抗性QTL培育抗病品种的策略也进行了探讨。
Rice black-streaked dwarf is a virus disease transmitted by the planthopper and has recently posed a serious threat to rice production in Jiangsu and Zhejiang provinces. In this study, based on the preliminary mapping of resistance genes of rice black-streaked dwarf disease, two resistant QTLs for tight linkage on the short arm of chromosome 6 were constructed. The resistant parent “Minghui63” was used as the donor , The susceptible parent “Huai 5” was a reincarnated parent. A series of near-isogenic lines carrying the targeted resistance QTLs were constructed by marker-assisted selection. Natural inoculation and artificial inoculation identification showed that the newly cultivated near-isogenic lines decreased their incidence by about 25% compared with the control recurrent parent and the resistance was significantly improved. The results of agronomic traits showed that most of the near-isogenic lines were similar to the reincarnated parents in their growth periods, plant height, yield traits and other characters, indicating that there were fewer cumbersome links in the target segments. In addition, strategies for fine mapping of how to achieve targeted QTLs and breeding of resistant varieties using marker-assisted selection and aggregation of multiple resistant QTLs were also explored.