Fighting a Worldwide Wheat Threat
By Kim Kaplan
June 16, 2008
Wheat stockpiles are at a 30-year low
and production costs are rising, but what really scares wheat growers is the
specter of Ug99, a new rust fungus to which very few of the currently grown
varieties of wheat are resistant.
But the seed of a solution may sprout this fall when
Agricultural Research Service (ARS)
scientists release the first wheat lines pyramiding two or more genes for
resistance to Ug99. One of these lines will be released this fall as a
specialty wheat for the eastern United States. Wheat breeders will be able to
use the new line along with others to develop new commercial varieties with
high yield and Ug99 protection.
ARS has a priority program tackling many aspects of Ug99 with a team of more
than 10 scientists, all of whom are keenly aware of Ug99's growing shadow,
which emerged in Uganda and has already spread to Kenya, Ethiopia, Sudan,
Yemen, and Iran. The scientists are located at ARS labs at
Among their tasks are determining U.S. wheat and barley vulnerability to
Ug99, identifying new sources of genetic resistance, discovering molecular
markers to speed up breeding for protection, developing rapid detection
methods, and nationwide surveillance for Ug99 in the United States.
To support the monitoring work, ARS has established "trap" plots
of wheat along known wheat rust pathways throughout the United States.
Of course, the ARS scientists are not going it alone. They're collaborating
with researchers across the country and around the world to find ways to deal
with this massive threat to a global food staple.
As part of this cooperation and collaboration, ARS coordinates sending
promising U.S. wheat varieties to Kenya and evaluating them for Ug99
resistance. This provides U.S. wheat breeders with a head start on protecting
the country's wheat. The screening is done in partnership with the
International Maize and Wheat Improvement
Center (CIMMYT), based in Mexico.
ARS has already evaluated more than 5,000 U.S. wheat lines in Africa through
this program. Results from the 2005-2007 screening showed that Ug99 has
overcome even more major resistance genes than previously believed.
ARS also will develop new sources of genetic resistance to rusts from three
wild relatives of wheat and make it easier to introduce those genes into
commercial wheat varieties.
ARS is a scientific research agency of the
U.S. Department of