以标记辅助选择改良江苏主栽粳稻品种“淮稻5号”黑条矮缩病抗性

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两个抗性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。

Using Marker-Assisted Selection to Improve the Resistance to Rice BlackStreaked Dwarf Viral Disease of Huaidao 5, an Elite Japonica Rice Cultivar in Jiangsu

Rice black-streaked dwarf viral disease (RBSDV), a kind of viral disease transmitted by small plant hopper, broke out recently in Jiangsu and Zhejiang provinces of China and posed a serious threat to rice production. Based on mapping of the QTLs for RBSDV resistance previously, we used the resistant parent Minghui 63 as donor, the susceptible japonica cultivar Huaidao 5 as recurrent parent, and bred a series of Near-isogenic lines (NILs) aiming at two closely linked QTLs on the short arm of Chromosome 6 in rice. Natural inoculation and artificial inoculation results showed that RBSDV incidence rate of NILs was about 25% lower than that of recurrent parent and the resistance of NILs was improved significantly. Agronomic traits of most NILs, such as heading date, plant height, and yield components were similar to those of recurrent parent, indicating that the target chromosome region contains few linkage drags. The strategies for fine mapping the target QTLs and pyramiding more QTLs in the way of breed improvement were also discussed.