Helping plant breeders develop new wheat varieties with improved disease resistance, stress tolerance and other desirable traits is the goal of Agricultural Research Service (ARS) scientists based at four regional small-grains genotyping centers.

Ranked third behind corn and soybeans in planted acreage and gross receipts, wheat is a major crop used in everything from flour and baked goods to crackers and pancakes. Yet insects and diseases pose a constant threat to the crop's productivity. Fortunately, new advances in the field of genomics are speeding scientists' identification of new traits to keep wheat healthy and productive in the face of these and other threats.

For example, at the ARS Western Regional Small Grains Genotyping Laboratory in Pullman, Wash., geneticist Deven See leads a team tasked with furnishing wheat and barley breeders in five states — Washington, Oregon, California, Idaho and Montana — with genetic profiles of their germplasm materials. See estimates at least 60 percent of genotyping requests received from breeders there are for genes conferring resistance to a fungal disease called stripe rust.

In Pacific Northwest production areas, stripe rust can inflict yield losses of up to 40 percent. Conventional methods of screening germplasm for resistance genes can take months to complete. Now, thanks to the genotypic services offered by See's group, coupled with the use of a technique called marker-assisted selection, breeders can identify resistant germplasm within a few days.

At the ARS Cereal Crops Research Unit in Fargo, N.D., molecular geneticist Shiaoman Chao is building a database to store genotypic information generated at her location as well as Pullman and two other regional small-grain genotyping centers: the ARS Plant Science Research Unit in Raleigh, N.C., and the ARS Plant Science and Entomology Research Unit in Manhattan, Kan.

Among their accomplishments, Chao and colleagues have genotyped 400 single nucleotide polymorphism DNA sequence variations in a selection of elite U.S. wheat cultivars that can be linked to desirable traits in the crop, expediting breeding efforts.