Directorate of Sorghum Research, Hyderabad, India.
Theor Appl Genet. 2011 May;122(8):1617-30. doi: 10.1007/s00122-011-1559-y. Epub 2011 Mar 9.
Shoot fly is one of the most important pests affecting the sorghum production. The identification of quantitative trait loci (QTL) affecting shoot fly resistance enables to understand the underlying genetic mechanisms and genetic basis of complex interactions among the component traits. The aim of the present study was to detect QTL for shoot fly resistance and the associated traits using a population of 210 RILs of the cross 27B (susceptible) × IS2122 (resistant). RIL population was phenotyped in eight environments for shoot fly resistance (deadheart percentage), and in three environments for the component traits, such as glossiness, seedling vigor and trichome density. Linkage map was constructed with 149 marker loci comprising 127 genomic-microsatellite, 21 genic-microsatellite and one morphological marker. QTL analysis was performed by using MQM approach. 25 QTL (five each for leaf glossiness and seedling vigor, 10 for deadhearts, two for adaxial trichome density and three for abaxial trichome density) were detected in individual and across environments. The LOD and R (2) (%) values of QTL ranged from 2.44 to 24.1 and 4.3 to 44.1%, respectively. For most of the QTLs, the resistant parent, IS2122 contributed alleles for resistance; while at two QTL regions, the susceptible parent 27B also contributed for resistance traits. Three genomic regions affected multiple traits, suggesting the phenomenon of pleiotrophy or tight linkage. Stable QTL were identified for the traits across different environments, and genetic backgrounds by comparing the QTL in the study with previously reported QTL in sorghum. For majority of the QTLs, possible candidate genes were identified. The QTLs identified will enable marker assisted breeding for shoot fly resistance in sorghum.
粘虫是影响高粱生产的最重要害虫之一。鉴定影响粘虫抗性的数量性状位点（QTL）可以帮助我们了解复杂相互作用的遗传机制和遗传基础。本研究的目的是利用 27B（敏感）×IS2122（抗性）杂交群体的 210 个 RIL 群体检测对粘虫抗性和相关性状的 QTL。在 8 个环境中对 RIL 群体进行了粘虫抗性（坏死芯百分比）表型分析，在 3 个环境中对叶片光泽度、幼苗活力和表皮毛密度等组成性状进行了表型分析。利用 149 个标记位点构建了连锁图谱，其中包括 127 个基因组微卫星、21 个基因微卫星和 1 个形态标记。利用 MQM 方法进行 QTL 分析。在单个和多个环境中检测到 25 个 QTL（叶光泽度和幼苗活力各 5 个，坏死芯 10 个，表皮毛密度 2 个，表皮毛密度 3 个）。QTL 的 LOD 和 R（2）（%）值范围分别为 2.44 至 24.1 和 4.3 至 44.1%。对于大多数 QTL，抗性亲本 IS2122 贡献了抗性等位基因；而在两个 QTL 区域，敏感亲本 27B 也为抗性性状做出了贡献。三个基因组区域影响多个性状，表明存在多效性或紧密连锁现象。通过比较本研究中的 QTL 与高粱中先前报道的 QTL，在不同环境和遗传背景下鉴定出稳定的 QTL。对于大多数 QTL，确定了可能的候选基因。鉴定出的 QTL 将有助于高粱抗粘虫的分子辅助育种。
