University of Wisconsin-Madison scientists have identified
bacteria that increased corn yields by 5 percent to 10 percent in
preliminary field trials in five Midwestern states.
"Ours is the first group to isolate and identify strains of
bacteria from inside plants that can increase corn yields," says
Eric Triplett, a microbial ecologist with the Department of
Agronomy. The discovery may lead to a new product for farmers — seed
corn that comes coated with growth-enhancing bacteria.
Corn is Wisconsin's leading crop. Last fall, farmers harvested
approximately 340 million bushels of corn from 2.6 million acres in
Triplett presented the findings last summer at a meeting in
Australia. The meeting attracted scientists from around the world
who are interested in bacteria that can supply nitrogen to crops
such as wheat, rice and corn. The Wisconsin research will be
published in the Australian Journal of Plant Physiology. The College
of Agricultural and Life Sciences scientists who worked on the
project included technician Patrick J. Riggs, graduate research
assistants Marisa Chelius and Leonardo Iniguez, and maize geneticist
Triplett began the research on corn after Brazilian scientists
discovered two bacteria that live inside sugar cane and produce all
the nitrogen the crop needs. The Wisconsin team then began a
systematic search for bacteria that live inside corn plants and can
capture nitrogen from the atmosphere.
The team evaluated 23 bacterial strains including ones from
Brazil and Egypt, along with several the UW-Madison researchers
isolated from corn and switch grass plants growing on nitrogen-poor
soils in Wisconsin. They eliminated most of the strains after
greenhouse tests and early field trials in Wisconsin.
The researchers found seven promising strains. Those strains
included two of the bacteria originally identified from sugar cane
and five that the team isolated in Wisconsin.
During 2000, the researchers conducted field trials with five
elite corn hybrids at the College's Arlington and Lancaster
Agricultural Research Stations, as well as at sites in Iowa,
Illinois, Nebraska and Indiana. The results showed that the bacteria
increased yields an average of 5 to 10 percent.
The scientists have applied for a patent on four of the bacterial
strains through the Wisconsin Alumni Research Foundation. Several
companies have express an interest in licensing the technology,
according to Triplett. He hopes that strains will be test marketed
within a few years.
Triplett says that it's not yet clear if the same bacterial
strains would enhance the yields of other corn hybrids. However, he
says, research shows that these strains will enter several other
plants including wheat and rice.
Just how the bacteria improve corn yields remains a mystery. It's
unlikely that the bacteria supply corn with a significant amount of
nitrogen, according to Triplett.
"We never found bacterial strains that could supply enough
nitrogen to compensate for nitrogen-deficient conditions," Triplett
says. "The field sites where we did the tests had plenty of
Triplett says finding bacteria that will supply corn with
nitrogen remains a long-term goal. Corn that requires little if any
nitrogen fertilizer could save Wisconsin farmers millions of dollars
in production costs each year while reducing problems associated
with too much nitrogen in the environment.
Triplett will continue studies to determine how the bacteria
enter corn plants and discover how they enhance yields.
The research was supported by state funding to the College of
Agricultural and Life Sciences, and by grants from the College,
Cargill, Inc., and the Consortium for Plant Biotechnology Research.