5-7-02
Contacts:Mark Westgate, Agronomy, (515) 294-9654Susan Thompson, Agriculture Communications, (515) 294-0705
PREDICTING CORN POLLEN MOVEMENT IS A KEY TO MAINTAINING GENETIC PURITY
AMES, Iowa -- It's been said that each summer a cloud of pollen forms over Iowa cornfields. The pollen produced in a particular cornfield doesn't fall just on plants within that field. That concerns hybrid seed corn producers, organic growers and other specialty corn growers who need to harvest and deliver a genetically pure product.
Researchers at Iowa State University are using a three-pronged approach to study the issue. The first step has been to develop a simple and consistent method of measuring the amount of pollen produced in a field.
Pollen traps, which are small plastic platforms with a sticky surface, are used to estimate the amount of pollen released each day. "We get the pollen to fluoresce, take their picture and use a computer to count the pollen grains," says Mark Westgate, an Iowa State plant physiologist.
Westgate uses this information to predict the daily rate of pollen production from measurements of tassel development. "This research will help seed companies determine more simply how much pollen their inbreds produce," Westgate says.
The second step has been to predict how far the pollen produced in a particular field will travel. Topography factors such as distance, elevation, windbreaks and border rows have an impact on pollen movement. So do atmospheric conditions such as wind speed and direction, air temperature and relative humidity.
Researchers at Iowa State developed a statistical model that treats each pollen grain as an individual particle and tracks its movement in the atmosphere. "This allows us to follow pollen movement over a wide range of fields and atmospheric conditions, through or around windbreaks, and test the impact of border rows," Westgate says.
The third step is to determine the impact that pollen from a neighboring field might have on the purity of hybrid seed corn or other specialty corn. Pollen entering from elsewhere must compete with locally shed pollen. This competition is controlled both by physical factors such as local pollen density, and genetic factors such as pollen-silk compatibility.
Westgate sees corn producers as the ultimate beneficiaries of the overall research effort. "The goal is to provide growers a rational and cost-effective method for isolating seed corn and other fields where they need to maintain a certain level of purity," he says. "It also will help growers predict the risk of out-crossing before harvest. If necessary, alternative uses for the crop can be sought earlier in the season, rather than after special handling and storage costs have been incurred."
-30-
RSS