Abstract Bacterial leaf blight (BLB) and blast are among the most destructive diseases of rice. In order to develop new varieties that can resist various races of the pathogens Xanthomonas oryzae pv. oryzae (Xoo) and Magnaporthe oryzae, which cause these two diseases, respectively, it is important to identify suitable markers and a marker-aided selection strategy. Seventeen foreground microsatellites associated with resistance against BLB and blast were screened for polymorphism for possible adoption in a breeding program for resistant cultivar development. A total of 472 background simple sequence repeats (SSRs) were also screened for polymorphism in order to recover the recurrent parent genome. All 72 F1 progenies were also analysed with the 17 foreground and 472 background markers in comparison to the alleles of their parents. The markers were validated using 218 BC2F2 plants. The result revealed six tightly linked polymorphic foreground markers (Xa21FR, pTA248, Xa13prom, MP, RM21 and RM13) associated with resistance against Xoo pathotype P7.7 and two microsatellites (RM6836 and RM8225) associated with resistance against blast pathotype P7.2. A total of 79 polymorphic background markers were identified for recovering the recurrent parent genome. The result also showed that the markers had goodness of fit (blast resistance) to 1:2:1 ratio for single gene model in BC2F2 progenies. These genetically confirmed microsatellite markers were recommended for use in marker-assisted backcross breeding and other marker-assisted selection of BLB and blast resistance genes in order to develop varieties with durable and broad spectrum resistance against the two major rice diseases.

中文翻译：

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水稻白叶枯病和稻瘟病抗性相关微卫星的遗传分析

摘要 细菌性叶枯病（BLB）和稻瘟病是对水稻危害最大的病害之一。为了开发能够抵抗各种病原体米黄单胞菌 pv. 的新品种。oryzae (Xoo) 和 Magnaporthe oryzae 分别引起这两种疾病，因此确定合适的标记和标记辅助选择策略很重要。筛选了 17 颗与 BLB 和稻瘟病抗性相关的前景微卫星的多态性，以便在抗性品种开发的育种计划中采用。还筛选了总共 472 个背景简单序列重复 (SSR) 的多态性，以恢复循环亲本基因组。与其亲本的等位基因相比，还使用 ​​17 个前景标记和 472 个背景标记分析了所有 72 个 F1 后代。使用 218 株 BC2F2 植物验证标记。结果显示六个紧密连锁的多态性前景标记（Xa21FR、pTA248、Xa13prom、MP、RM21 和 RM13）与对 Xoo 致病型 P7.7 的抗性相关，以及两个微卫星（RM6836 和 RM8225）与对爆炸致病型 P7.2 的抗性相关。总共鉴定了 79 个多态性背景标记，用于恢复循环亲本基因组。结果还表明，标记对 BC2F2 后代中的单基因模型具有 1:2:1 的拟合优度（抗瘟性）。这些经遗传证实的微卫星标记被推荐用于标记辅助回交育种和其他标记辅助选择 BLB 和稻瘟病抗性基因，以开发对两种主要水稻病害具有持久和广谱抗性的品种。