Sorghum (Sorghum bicolor (L.) Moench) is an important food crop in semi-arid tropics. The crop grain yield ranges from 0.5 t/ha to 0.8 t/ha compared to potential yields of 10 t/ha. The African stem borer Busseola fusca Fuller (Noctuidae) and the spotted stem borer Chilo partellus Swinhoe (Crambidae), are among the most economically important insect pests of sorghum. The two borers can cause 15% - 80% grain yield loss in sorghum. Mapping of QTLs associated with resistance traits to the two stem borers is important towards marker-assisted breeding. The objective of this study was to map QTLs associated with resistance traits to B. fusca and C. partellus in sorghum. 243 F_9:10 sorghum RILs derived from ICSV 745 (S) and PB 15520-1 (R) were selected for the study with 4,955 SNP markers. The RILs were evaluated in three sites. Data was collected on leaf feeding, deadheart, exit holes, stem tunnels, leaf toughness, seedling vigour, bloom waxiness, and leaf glossiness. ANOVA for all the traits was done using Genstat statistical software. Insect damage traits and morphological traits were correlated using Pearson’s correlation coefficients. Genetic mapping was done using JoinMap 4 software, while QTL analysis was done using PLABQTL software. A likelihood odds ratio (LOD) score of 3.0 was used to declare linkage. Joint analyses across borer species and sites revealed 4 QTLs controlling deadheart formation; 6 controlling leaf feeding damage; 5 controlling exit holes and stem tunneling damages; 2 controlling bloom waxiness, leaf glossiness, and seedling vigour; 4 conditioning trichome density; and 6 conditioning leaf toughness. Joint analyses for B. fusca and C. partellus further revealed that marker CS132-2 colocalised for leaf toughness and stem tunneling traits on QTLs 1 and 2, respectively; thus, the two traits can be improved using the same linked marker. This study recommended further studies to identify gene(s) underlying the mapped QTLs.

中文翻译：

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高粱 (Sorghum bicolor) 非洲二化螟 (Busseola fusca) 和斑二化螟 (Chilo patellus) 双重抗性相关性状 QTL 作图


高粱（ Sorghum bicolor (L.) Moench）是半干旱热带地区的重要粮食作物。农作物产量为 0.5 吨/公顷至 0.8 吨/公顷，而潜在产量为 10 吨/公顷。非洲二化螟Busseola fusca Fuller（Noctuidae）和斑点二化螟Chilo patellus Swinhoe（Crambidae）是高粱最重要的经济害虫之一。这两种蛀虫可造成高粱籽粒减产15%～80%。与两种螟虫抗性相关的 QTL 作图对于标记辅助育种非常重要。本研究的目的是定位与高粱中B. fusca和C. patellus抗性性状相关的 QTL。选择源自 ICSV 745 (S) 和 PB 15520-1 (R) 的 243 F _9:10高粱 RIL 进行研究，具有 4,955 个 SNP 标记。 RIL 在三个地点进行了评估。收集有关叶子取食、死心、出口孔、茎隧道、叶子韧性、幼苗活力、花朵蜡质和叶子光泽度的数据。使用 Genstat 统计软件对所有性状进行方差分析。使用皮尔逊相关系数将昆虫损害性状和形态性状相关联。使用JoinMap 4软件进行遗传图谱分析，使用PLABQTL软件进行QTL分析。使用 3.0 的似然优势比 (LOD) 分数来声明关联。跨螟种和地点的联合分析揭示了 4 个控制死心形成的 QTL； 6控制叶片取食危害； 5 控制出口孔和阀杆掘进损伤； 2 控制花蜡度、叶片光泽度、幼苗活力； 4.调节毛状体密度；和6调理叶片韧性。 B. fusca和C.的联合分析 partellus 进一步揭示，标记CS132-2分别与 QTL 1 和 2 上的叶片韧性和茎隧道性状共定位；因此，可以使用相同的连锁标记来改善这两个性状。这项研究建议进一步研究以确定所映射的 QTL 背后的基因。