Scientists Set to Release New Disease-Resistant
Wheat By Jan
Suszkiw December 4, 2007
'Mace', a new winter wheat cultivar developed by Agricultural Research
Service (ARS) scientists and cooperators,
could give growers an added measure of insurance against outbreaks of wheat
streak mosaic virus (WSMV).
According to ARS plant geneticist
Graybosch, Mace harbors a gene called Wsm-1 that confers resistance
to the virus, which is spread by the wheat curl mite, Aceria tosichella.
Spraying pesticide to prevent the mite from feeding and transmitting
WSMV isn't particularly effective, so growers typically resort to using a
combination of strategies, such as controlling weedy grasses and "volunteer"
wheat. Both are sources of WSMV that the mites can acquire through feeding.
Even then, outbreaks of the virus can still occur. In the Great
Plains, yearly outbreaks of WSMV claim about five percent of the region's wheat
crop. Losses can be higher, as was the case in 1995, when an outbreak in
Montana caused $35 million in yield losses there.
This winter, following more than 10 years of research, development and
evaluation, Mace will be made available to wheat breeders and growers as
foundation seed. 'RonL', a Kansas State
University release, is the only other U.S. wheat cultivar with resistance
to WSMV. However, this resistance seems to fade when temperatures climb to 70
degrees Fahrenheit or higher, notes Graybosch. He works at the
Grain, Forage and Bioenergy Research Unit in Lincoln, Neb.
Temperature sensitivity isn't an issue with Mace, which inherited its
virus resistance from CI 17884, a wheat germplasm line that carries a
chromosome for the trait from an intermediate wheatgrass. Graybosch codeveloped
and tested the new wheat line with scientists at the ARS Lincoln unit, the
University of Nebraska, and Kansas State
In two years of field trials at sites throughout Nebraksa, Mace
produced grain yields equal to 'Wesley' and 'Millennium', two commercial
varieties. In virus-infected fields, however, Mace's yields were two to three
times higher than these and other commercial varieties the scientists used for
Graybosch is handling seed requests for the new wheat line.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.