By Rebekah Ray

MISSISSIPPI STATE -- Aflatoxin takes its toll on Mississippi corn production, but two scientists at Mississippi State University have recently released a weapon to fight the fungus.

U.S. Department of Agriculture's Agricultural Research Service plant geneticist Paul Williams and plant pathologist Gary L. Windham developed the germplasm Mp715 that was released by the USDA-ARS and the Mississippi Agricultural and Forestry Experiment Station.

"Aflatoxin research has been underway at MSU for more than 20 years, but as corn becomes more popular in Mississippi, the need for this research increases," Williams said. "Unlike the Midwest corn-producing states, Mississippi growers have to contend with extreme heat, humidity and drought-stressed plants almost every year. All three of those weather factors are conducive to aflatoxin development."

Grain containing aflatoxin is toxic to animals. Grain elevators reduce prices for infected corn or reject whole truckloads if the contamination is extreme. Williams said estimated losses in Mississippi, Louisiana and Texas due to aflatoxin exceeded $85 million in 1998.

Germplasms such as Mp715 introduce superior genetic traits into existing seeds for production of improved crops. Mp715 was developed from the variety Tuxpan in a selective breeding program aimed at developing plants resistant to aflatoxin contamination.

"While developing the germplasm is an important step in creating a resistant plant, the process of making a marketable hybrid can take 10 years or more," Williams said. "Mp715 is the third germplasm line we've released, with the last one released in 1991. There are no hybrids with aflatoxin resistance available to growers. Researchers with commercial seed corn companies are still working on developing aflatoxin-resistant hybrids that perform well."

Few other methods have been used successfully to fight aflatoxin. Producers can minimize the threat by harvesting early and reducing fungal exposure to warm, humid conditions during dry down by artificially drying the corn. Wet grain that is not dried quickly during warm conditions will begin heating up and aflatoxin will increase to intolerable levels rapidly.

Corn production dominates American agriculture. The United States is the world's largest exporter of corn, supplying 80 percent of the world demand.

Mississippi corn growers in 1998 posted a second year of significant declines. After a record 1996 crop, corn's value drop about 35 percent in 1997 and was estimated to drop another 38 percent in 1998. Corn's farm gate value changed from almost $204 million in 1996 to $133 million in 1997. For 1998, the estimated corn value was $82.4 million.

Editor's Note: Linda Breazeale contributed to this article.
Contact: Paul Williams, (601) 325-2735 or Gary Windham, (601) 323-2230