Genetic Mapping and Development of Kasp Markers for Hessian Fly Resistance Gene H32 in Wheat.

Hessian fly [Hf, Mayetiola destructor (Say)] is one of the most destructive insect pests of wheat (Triticum aestivum L) throughout wheat production areas of United States and worldwide. Breeding for wheat cultivars with resistance is the most feasible strategy to minimize losses caused by Hf. In parallel, development of breeder friendly markers linked to Hf resistance genes is essential in wheat breeding through marker-assisted selection (MAS). At least 33 genes for resistance to Hf have been identified in wheat and its relatives. The Hf resistance gene H32 that was mapped on the long arm of 3D (3DL) is particular valuable for wheat breeding programs because it confers a broad spectrum of resistance including the highly virulent Hf biotype L to the least virulent Hf biotype Great Plains (GP). In this study, we tested 188 doubled-haploid (DH) lines derived from the cross of a synthetic line W7984 and spring wheat ‘Opata 85’ for response to Hf biotypes L and GP. W7984 is Hf-resistant with H32 gene while Opata 85 is Hf-susceptible. Three sets of marker data with two genotyping-by-sequencing (GBS) and one 90K array single nucleotide polymorphisms (SNPs) were used to construct genetic maps. The H32 resistance to biotype L and biotype GP was mapped within a 2.2 to 2.5 cM interval on 3DL between two closely linked SNP markers. These closely linked markers are being converted to Kompetitve Allele Specific PCR (KASP) assay and will be validated for MAS of H32 in germplasm and breeding material. Development of these breeder friendly markers that are tightly linked to H32 will facilitate MAS to accelerate the transfer of H32 to improve wheat varieties with more accuracy.