Thwarting Russian Wheat Aphids--Again
By Luis
Pons April 8, 2004
Past Agricultural Research
Service work to control Russian wheat aphids may pay off again, this time
against a new biotype of the insect.
Russian wheat aphids are major pests of cereal crops. The
original biotype has cost American wheat and barley farmers billions of dollars
in losses since first appearing in the United States in 1986.
The new biotype, first spotted in Colorado last year, overcomes
the genetic defenses of many wheat and barley lines developed to combat the
original aphid. These lines were developed at the ARS
Wheat, Peanut and Other Field Crops
Research Unit in Stillwater, Okla., and at the
Small Grains and Potato
Germplasm Research Unit in Aberdeen, Idaho.
In Stillwater, entomologist James Webster and geneticists Cheryl
Baker and Dolores Mornhinweg reacted to the discovery of the first aphid
biotype by screening 30,000 wheat and 24,000 barley germplasm accessions for
resistance traits for incorporation into new crop lines. Most of that germplasm
was obtained from the Aberdeen unit's
National Small
Grains Collection.
That work led to identification of more than 300 resistant wheat
germplasm lines and 40 promising barley germplasm lines.
Now, the new biotype has led Baker and Mornhinweg to re-examine
breeding lines they developed during the first crisis. Mornhinweg tested about
one-third of the barley lines found to be resistant to the original aphid and
discovered they were resistant to the new type. Also, four breeding lines of
winter barley and three feed barleys set to be released within the next few
years show resistance to both aphid biotypes.
Baker has found strong candidates among the advanced wheat
lines, including a promising one derived from a wheat-rye line she received
from a South African scientist.
Read more
about the research in the April issue of Agricultural Research
magazine.
ARS is the U.S. Department of
Agriculture's chief scientific research agency. |