Muturi Phyllis W, Mgonja Mary, Rubaihayo Patrick, Mwololo James K
Department of Agricultural Resource Management, University of Embu, P.O. Box 60100, Embu, Kenya.
Alliance for a Green Revolution in Africa, P.O. Box 34441, Dar es Salaam, Tanzania.
Int J Genomics. 2021 Jan 15;2021:7016712. doi: 10.1155/2021/7016712. eCollection 2021.
Sorghum ( (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 Fuller (Noctuidae) and the spotted stem borer 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 and in sorghum. 243 F 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 and further revealed that marker 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.
高粱（(L.) Moench）是半干旱热带地区的一种重要粮食作物。与潜在产量10吨/公顷相比，该作物的谷物产量在0.5吨/公顷至0.8吨/公顷之间。非洲高粱条螟Fuller（夜蛾科）和高粱点螟Swinhoe（草螟科）是高粱最重要的经济害虫。这两种螟虫可导致高粱产量损失15% - 80%。绘制与这两种茎螟抗性性状相关的QTL图谱对于标记辅助育种至关重要。本研究的目的是绘制高粱中与对这两种茎螟抗性性状相关的QTL图谱。从ICSV 745（感虫）和PB 15520 - 1（抗病）衍生的243个F代高粱重组自交系（RILs）被选用于该研究，使用了4955个单核苷酸多态性（SNP）标记。这些RILs在三个地点进行了评估。收集了关于叶片取食、枯心、羽化孔、茎隧道、叶片韧性、幼苗活力、开花蜡质和叶片光泽的数据。使用Genstat统计软件对所有性状进行方差分析。使用Pearson相关系数对昆虫危害性状和形态性状进行相关性分析。使用JoinMap 4软件进行遗传图谱构建，而使用PLABQTL软件进行QTL分析。使用3.0的似然比（LOD）得分来判定连锁。跨螟虫种类和地点的联合分析揭示了4个控制枯心形成的QTL；6个控制叶片取食危害的QTL；5个控制羽化孔和茎隧道危害的QTL；2个控制开花蜡质、叶片光泽和幼苗活力的QTL；4个调节毛状体密度的QTL；以及6个调节叶片韧性的QTL。对这两种茎螟的联合分析进一步揭示，标记分别在QTL 1和QTL 2上与叶片韧性和茎隧道性状共定位；因此，这两个性状可以使用相同的连锁标记进行改良。本研究建议进一步开展研究以鉴定已定位QTLs的潜在基因。
