Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2010
Publication Date: 5/21/2010
Citation: Yu, G., Williams, C.E., Harris, M.O., Cai, X., Mergoum, M., Xu, S.S. 2010. Development and Validation of Molecular Markers Closely LinKed to H32 for Resistance to Hessian Fly in Wheat. Crop Science. 50:1325-1332. Interpretive Summary: Two wheat genes conferring resistance to Hessian fly were mapped previously to similar locations in the wheat genome leaving the relationship between the genes unclear. New markers for marker-assisted breeding were developed and in mapping their location it was demonstrated that the two resistance genes are either located very near each other in the genome or are alternative forms of the same gene. This information will be useful to wheat breeders wanting to use marker-assisted breeding to move either or both of these resistance genes into new cultivars in order to limit the damage of Hessian fly to the wheat crop.
Technical Abstract: Hessian fly is an important insect pest of wheat. Host resistance-plant resistance has been the most effective means to manage this insect. A total of 32 Hessian fly-resistance genes have been identified in wheat and its relatives. Hessian fly-resistance genes H26 and H32, conferring resistance to multiple biotypes of Hessian fly, were assigned to the same chromosomal bin 3DL3-0.81-1.00 on the long arm of wheat chromosome 3D (3DL) in previous studies. The objective of this study was to determine the genetic relationship between the two resistance genes through comparative mapping. H32 was previously mapped in the ITMI population of 129 inbred lines and H26 in a population of 96 F2 individuals. Fourteen wheat EST-derived STS markers flanking the H26 locus were assigned to the linkage map of H32 in the ITMI population. Two of the STS markers, Xrwgs10 and Xrwgs12, were found to flank the H32 locus with a genetic distance of 0.5 cM on either side of H32. Xrwgs10 is 3.2 cM distal to H26 and Xrwgs12 is 1.0 cM proximal to H26 on the genetic map of H26. Another STS marker Xrwgs11, which is 1.0 cM proximal to H26, co-segregated with H32 in the ITMI population. This comparative mapping analysis suggested that H26 and H32 are likely allelic or closely linked to each other. Molecular markers tightly linked to these two Hessian fly resistance genes or alleles were validated in 13 bread wheat cultivars and an advanced breeding line, demonstrating the efficacy of these markers for marker-assisted selection in breeding for Hessian fly-resistance in wheat.