Researchers also predicting pollen movement from GM crops
MADISON, WI - 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.


[www.eurekalert.org]