Nursery is New Tool in Fight against Ug99 Wheat Stem
February 26, 2010
The first Winter Wheat Stem Rust
Resistance Nursery, a key tool in the fight against the rust strain Ug99, has
been established by the Agricultural Research Service (ARS) and international
The nursery, established by ARS and the International Maize and Wheat Improvement
Center (CIMMYT), is located in Ankara, Turkey, where CIMMYT coordinates its
global winter wheat breeding program. It is the first of its kind for winter
wheats, and is a joint effort to distribute 100 lines that have been identified
by international scientists as having resistance to the deadly Ug99 stem rust
and its descendants.
Thirty of the 100 lines in the nursery were developed by ARS scientists and
contain resistance to stem rust races in Kenya and the United States. The lines
developed by ARS focus on the use of four or five resistance genes that have
been incorporated into various combinations in winter wheat lines.
Marshall, research leader of the
Plant Science Research Unit in Raleigh, N.C., and coordinator of the wheat
screening conducted in Kenya, multiple genes for resistance will slow the
pathogens ability to readily overcome the new wheat varieties that
breeders develop. The amount of time these genes can remain effective is key to
maintaining resistance to stem rust in the United States.
Winter wheat lines in the nursery are being distributed by CIMMYT to wheat
breeders and geneticists in 34 countries, including those that have been hit
hardest by the disease.
Ug99, Puccinia graminis f. sp. tritici, is the most virulent race of
stem rust fungus yet to emerge. First discovered in Uganda in 1999, the fungus
has spread across Africa, Asia and the Middle East. Ug99 has been able to
overcome most of the stem-rust-resistant wheat varieties developed during the
past several decades. While other rusts only partially affect crop yields, Ug99
can wipe out entire wheat fields, resulting in 100 percent crop loss.
more about this research in the February 2010 issue of Agricultural
ARS is the principal intramural scientific research agency of the
U.S. Department of Agriculture (USDA). This
research supports the USDA priority of promoting international food security.