Two new varietiesand 50 new germplasm linesof barley that resist all known types of Russian wheat aphid (RWA) now affecting the western Great Plains have been released by Agricultural Research Service (ARS) scientists and their collaborators.
This is great news for the region's barley industry, which, for two decades, has been stymied by the invasive pest.
The new offerings resist damage from the original RWA that began devastating Plains barley in 1986, as well as from five new races of the pest found since 2003. The aphid has halted barley production in parts of eastern Colorado and Wyoming, and in parts of western Nebraska and Kansas.
The releases are a payoff from a 12-year project in which plant geneticist Dolores Mornhinweg in the ARS Wheat, Peanut and Other Field Crops Research Unit at Stillwater, Okla., teamed with geneticists Phil Bregitzer and Donald Obert in the ARS Small Grains and Potato Germplasm Research Unit at Aberdeen, Idaho. Their objective is to introduce RWA-resistant genes to every commercial barley type grown in the United States.
The new varietiesnamed Sidney and Stonehamare drought-hardy spring feed barleys. They were developed through crossing of RWA-resistant barley material with Otis, a feed variety that was bred for drought-susceptible eastern Colorado but has been decimated by the RWA. They are the result of collaborative work between ARS, Colorado State University and the University of Nebraska.
Also released were 36 spring germplasm lines of malting barley, and 14 germplasm lines of feed barleyseven each for spring and winter planting.
Since the main feature of the new barley releases is tolerance, aphids can be present on the plants without damaging them, according to Mornhinweg.
She has screened the entire collection of barley accessions at Aberdeen's National Small Grains Collection, identifying 109 samples with some level of RWA resistance. According to Mornhinweg, the new releases involve 37 sources of RWA resistance found during this screening.
ARS is the U.S. Department of Agriculture's chief scientific research agency.