22, 2005, ARS News Service: The first soybean
line with genetic resistance to charcoal rot has been
released by Agricultural Research Service scientists
Charcoal rot, caused by the soilborne fungus Macrophomina
phaseolina, is a major yield-limiting disease of the
Mid-South and other soybean-producing regions throughout
The new line, DT97-4290, developed by scientists in
the ARS Crop Genetics and Production Research Unit at
Stoneville, is a potentially valuable source of resistance
to charcoal rot for soybean breeders and producers in
areas experiencing yield losses due to the disease.
Charcoal rot symptoms usually appear when weather conditions
are hot and dry, causing the soybean plant to lose vigor.
In more advanced stages, petioles and leaves may turn
yellow and wilt, while remaining attached to the plant.
No chemical controls currently exist for charcoal rot,
and resistance has been hard to identify.
Field studies were conducted at Stoneville to find
charcoal rot resistance among 24 selected soybean genotypes.
The researchers identified three breeding lines with
genetic resistance, according to Bob Paris, the research
geneticist who developed the line with Alemu Mengistu,
a soybean pathologist.
The new line was selected for its adaptation to the
clay soils of the lower Mississippi River valley, and
for its field resistance to charcoal rot, soybean mosaic
virus and stem canker, and moderate resistance to frogeye
Genetic material of this release will be deposited
in the National Plant Germplasm System, where it will
be available for soybean researchers and breeders.