Identification of microsatellite markers associated with a stem solidness locus in wheat

Wheat stem sawfly (WSS), Cephus cinctus N., is a major insect pest of winter and spring wheat, Triticum aestivum L., in areas of the northern Great Plains. The primary control measure is use of resistant cultivars containing solid stems. Environmental effects on expression of the trait can be problematic, thus genetic markers would be useful. In this study, a doubled haploid (DH) winter wheat population derived from a 'Rampart' (solid stems) X 'Jerry' (hollow stems) cross was analyzed to identify molecular markers linked to genes controlling stem solidness. The DH population was genotyped with GWM and BARC microsatellite primers that spanned the wheat genome. To genotype the population efficiently, bulked segregant analysis (BSA) was used to identify polymorphism between groups of solid stem and hollow stem individuals. Four microsatellite markers (GWM247, GWM340, GWM547, and BARC77) were found linked to a single solid stem QTL (designate Qss. msub-3BL) on chromosome 3BL. However GWM247, GWM340, and GWM547 were found to be more closely linked to the QTL than BARC77. Single marker analysis showed Qss.msub-3BL contributes at least 76% of the total variation for stem solidness. Additionally, no significant relationship existed between Qss.msub-3BL and other agronomic traits, including yield. These microsatellite markers (GWM247, GWM340, and GWM547) will be useful for selecting solid-stemmed wheat cultivars to help control the wheat stem sawfly.