Protecting
Sugar Beets From Root Diseases
By David
Elstein
August 17, 2004 Four sugar beet lines with resistance
to a key root disease have been found in the
National Plant Germplasm System
collection by an Agricultural Research
Service scientist.
The lines are resistant to Rhizoctonia root rot, the most common and serious
fungal root disease of sugar beets in the United States. Sugar beets account
for more than half the sugar produced in the United States.
ARS plant pathologist Linda E. Hanson, based at the
Sugar Beet Research Unit in Fort
Collins, Colo., tested 36 plant introductions, including wild and garden beets,
from the plant germplasm system. She inoculated the beets with Rhizoctonia
fungi and later compared them to more susceptible varieties during hot,
Colorado summer weather that helped the disease to flourish. She found four
lines that had healthy roots, compared to the susceptible varieties that were
infected.
While there are already some disease-resistant sugar beets, researchers want
to develop new lines in case current varieties become susceptible.
In addition to causing yield losses of up to 50 percent in the field,
Rhizoctonia root rot can reduce storage and processing qualities in harvested
beets.
Most of the lines Hanson studied are not available yet commercially. But ARS
geneticist and research leader Leonard W. Panella will use some of the
successful plant introductions in breeding new lines. The new germplasm, if
proven successful at resisting the disease and producing high yields, will be
used for a future release.
Hanson and Panella are also hoping to figure out why certain lines are
resistant to diseases; they want to see the genetics behind the disease
response. They may be able to apply that knowledge to other crops that suffer
from Rhizoctonia root rot, such as soybeans. Their research is part of a
national program to screen plant introductions for resistance to 10 important
disease and insect pests.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.
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