Madison, Wisconsin
September 18 2007
Recently, researchers at
Iowa State University
discovered a way to increase the accuracy of a popular crop
model. By zeroing in on early stages leading up to kernel
formation, scientists believe they can help improve yield
predictions across a variety of environmental conditions. The
team of scientists reported their findings in the
September-October issue of Crop Science.
The Crop Environment Resource Synthesis (CERES)- Maize model is
used worldwide to predict maize yield each growing season.
CERES-Maize predictions are based upon simulations of plant
growth and the amount of carbon and nitrogen maize plants
accumulate each day. While this approach provides growers with
ballpark estimates of maize production, the accuracy decreases
when growing conditions affect kernel formation more than plant
growth.
Unlike most crop plants, maize has separate male and female
flowers. Pollen from male flowers must travel to and fertilize
female flowers located on ear. Each successful fertilization of
a female flower leads to the production of a kernel.
“Pollination success depends on the amount of viable pollen
produced, the presence of the pollen receptive part of the
female flower, and close synchrony in male and female flower
development,” says Mark Westgate, Iowa State University
professor of agronomy. “CERES-Maize does not consider these
critical aspects of the pollination process.”
To overcome the limitations of CERES-Maize, Westgate and his
colleagues developed algorithms for a Flowering Model to
simulate maize flowering dynamics. Once they were convinced the
Flowering Model was properly imitating maize flowering patterns,
they coupled it to CERES-Maize. The Modified version of
CERES-Maize then was calibrated against two years of field data
involving three hybrids, eight population densities, and seven
nitrogen levels. The Modified version of CERES-Maize generated
more accurate predictions of maize yield across a wide range of
growing conditions.
“There are many situations in which kernel number is not limited
by the ability of the plant to supply carbon and nitrogen to the
ear,” Westgate said. “By taking into account other factors
influencing kernel number, CERES-maize is much more sensitive to
biological factors that can affect yield.”
What’s up next for Westgate and his research team? A model they
are developing to predict pollen movement from one field to
another. They're using it along with the Flowering Model to
predict the genetic purity of harvested seed. According to
Westgate, genetic purity is a concern in hybrid seed production
as well as for corn grown for non-genetically modified markets.
Crop Science, is a
peer-reviewed, international journal of crop science published
bimonthly by the Crop Science Society of America.
ASA,
CSSA and
SSSA are educational
organizations helping their 11,000+ members advance the
disciplines and practices of agronomy, crop, and soil sciences
by supporting professional development and science policy
initiatives, and by providing quality, research-based
publications, and a variety of member services.
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