Ames, Iowa
November 12, 2007
Source: Integrated Crop Management - November 12, 2007
by Greg Tylka, Department of Plant Pathology,
Iowa State University
There are hundreds of resistant
soybean varieties available for use in managing the soybean cyst
nematode (SCN), a serious yield-limiting pest of soybeans.
SCN-resistant soybean varieties are not immune; they can allow
up to 10 percent SCN reproduction. Allowing 10 percent or less
reproduction means the soybean varieties are providing 90
percent control.
The amount of SCN reproduction that occurs on any individual
SCN-resistant soybean variety is determined by the genetics of
the soybean plant and the genetics of the SCN population present
in the field where the variety is being grown. The suppression
of SCN reproduction afforded by most SCN-resistant soybean
varieties allows for profitable management of SCN in the field.
The Iowa State University SCN-resistant Soybean Variety Trial
Program evaluates for Iowa growers and their advisers the yield
and SCN control provided by SCN-resistant soybean varieties. Not
all SCN-resistant varieties are equal in yield or the nematode
control that they provide. Soil samples are collected from each
four-row, variety-trial plot (10 soil cores from the center two
rows of each plot) at the time of planting and analyzed to
verify the presence of SCN in every plot. At harvest, another
soil sample is collected from each plot, and SCN population
densities are determined to assess how well the SCN population
reproduced on the soybean variety grown in each plot. Commonly
grown SCN-susceptible varieties also are included in each of the
variety trials.
Full article:
http://www.ipm.iastate.edu/ipm/icm/2007/11-12/scntrials.html
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