Submitted to: Mycotoxin Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 5, 2005
Publication Date: September 1, 2006
Citation: Williams, W.P. 2006. Breeding for resistance to aflatoxin accumulation in maize. Mycotoxin Research. 22:27-32. Interpretive Summary: Aflatoxin is produced by the fungus Aspergillus flavus. It is toxic to livestock and causes cancer in humans. Contamination of corn with aflatoxin generally increases with drought, high temperatures, and insect damage. Its presence in corn grain substantially reduces value and marketability of the grain. Growing corn hybrids that have resistance to A. flavus infection and aflatoxin contamination is considered the best option for reducing losses to aflatoxin contamination of corn. A breeding program established by USDA-ARS at Mississippi State University has identified corn germplasm that exhibits resistance to aflatoxin contamination. Several germplasm lines with resistance to aflatoxin contamination have been developed and released to the public. Research to identify genes that confer resistance is underway. Development and release of aflatoxin-resistant corn germplasm lines and identification of genes that can be used as molecular markers in commercial corn breeding programs will significantly enhance efforts to develop high quality aflatoxin-resistant corn hybrids.
Technical Abstract: Contamination of maize, Zea mays L., grain with aflatoxin, a naturally occurring toxin produced by Aspergillus flavus, frequently reduces the value and marketability of maize produced in the southern USA. Drought, high temperatures, and insect damage are often associated with high levels of aflatoxin contamination. Growing resistant maize hybrids is generally considered the most feasible method of reducing or eliminating A. flavus infection and subsequent accumulation of aflatoxin. Developing appropriate screening techniques and identifying maize germplasm with resistance to aflatoxin contamination provides the foundation for a breeding program. Only a few sources of aflatoxin resistance have been identified. Four germplasm lines, Mp313E, Mp420, Mp715, Mp717, have been developed and released by USDA-ARS at Mississippi State University. Conventional phenotypic selection was used to successfully combine resistance to aflatoxin contamination from two of these lines, Mp313E and Mp715, with desirable agronomic qualities from Va35. The identification of quantitative trait loci (QTL) associated with resistance to aflatoxin contamination will also permit the use of marker assisted selection in transferring resistance into elite germplasm lines. Development of parental inbreds that combine aflatoxin resistance with superior agronomic quality is an essential component of a hybrid maize breeding program designed to reduce or eliminate aflatoxin contamination of maize.