Wheat Germplasm Development and Genetic Mapping for Hessian Fly Resistance.

Wheat (Triticum aestivum) is the most widely grown cereal, and a primary source of protein and calories consumed by humans. However, it’s production is frequently challenged by diseases and pests. Hessian fly (HF; Mayetiola destructor), also known as gall midge, is an important insect pest of wheat that results in 5-10% annual yield loss in the US alone. HF has thirteen reported biotypes designated as A-L and GP. GP is the prevalent biotype in Kansas and is one of the most virulent biotypes. Seven of the 35 identified genes provide resistance to GP biotype, and all are mapped on short arm of chromosome 1A. HF resistance genes fit gene-for-gene model that put strong selection pressure on the insects causing HF to evolve faster and overcome resistance. As the resistance genes fail often, it is imperative to keep up with the discovery of new genes that can be quickly deployed in a breeding program. We have identified a new HF resistance gene in ‘Overley’ x Aegilops tauschii population. Initial screening and phenotypic distribution has indicated that it is a single dominant gene. The analysis of genotyping-by-sequencing of 92 resistant and susceptible lines have mapped this gene on distal end of the long arm of chromosome 3D. This germplasm will be available for the plant breeding community under Wheat Genetics Resource Center guidelines. Developing wheat varieties with built in host resistance is an effective and sustainable way to control HF.