|
 Genetic
markers may provide a fast means to accurately identify
races of soybean cyst nematodes and give farmers a more
responsive tool for defending against these destructive
microscopic worms.
"Soybean cyst nematodes are the number one problem
for soybeans in the United States and, probably, the
world," says Bob Riggs, University of Arkansas Division
of Agriculture nematologist.
"In a dry year, non-irrigated soybeans infested with
soybean cyst nematodes can suffer a 10 to 30 percent
yield loss," he says. In a study funded by the Arkansas
Soybean Promotion Board, Riggs and post-doctoral researcher
Shouhua Wang are applying a new molecular biology technique
to the identification of SCN races. The amplified fragment
length polymers technique, or AFLP, is the most powerful
method available for DNA fingerprinting of microorganisms.
"If we have a sufficient sample, this technique will
take, at most, one week to identify cyst nematode races,"
Wang says. Current methods take four to five weeks.
"We have established that AFLP can be used to differentiate
the races, so this is very important," Wang says. "No
other fingerprinting technique has permitted us to tell
as much difference."
Riggs and Wang are using identified SCN samples from
across the country, as well as other countries, to find
genetic indicators that can differentiate the 16 known
SCN races. Riggs says there is no known method that
can eradicate SCN from infested soil, including keeping
susceptible plants out of a field. No high-yielding
soybean variety is resistant to all SCN races, so knowing
which races are present in an infested field is essential
to selecting a variety that will thrive.
"In any given year, 65 to 75 percent of Arkansas'
soybean acreage is infested with soybean cyst nematodes,"
Riggs says.
Nematodes infest the plants' root systems, distorting
the tissues that transport water up to the food-producing
tissues. Impaired water movement in a plant can result
in yellow leaves and stunted growth.
"My advice to farmers when they find soybean cyst
nematodes is to rotate their crops according to U of
A Division of Agriculture recommendations," he says.
"Rotating crops suppresses population growth of SCN,
and one year with a non-host crop can reduce a population
75 percent."
Soybeans Today January 2000
Table of Contents
About
the ASPB | ASPB
Programs | Publications
Research Results
| Arkansas Ag
Statistics | Internet
Resources
Homepage | Live Dealer
For additional information about any board-related
activity contact:
Arkansas
Soybean Promotion Board
ATTN: Warren Carter
P.O. Box 31
Little Rock, AR 72203-0031
Phone: 501-228-1265.
Copyright �2000 Arkansas
Soybean Promotion Board.
All rights reserved.
|
