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ARS Home » Southeast Area » Mississippi State, Mississippi » Crop Science Research Laboratory » Corn Host Plant Resistance Research » Research » Publications at this Location » Publication #304094

Research Project: Genetic Improvement of Maize with Enhanced Resistance to Aflatoxin and Insects

Location: Corn Host Plant Resistance Research

Title: Identifying and developing maize germplasm with resistance to aflatoxin contamination

Author
item Williams, William
item Krakowsky, Matthew
item Scully, Brian
item Brown, Robert
item Menkir, Abede - International Institute Of Tropical Agriculture (IITA)
item Warburton, Marilyn
item Windham, Gary

Submitted to: World Mycotoxin Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/3/2014
Publication Date: 2/1/2015
Citation: Williams, W.P., Krakowsky, M.D., Scully, B.T., Brown, R.L., Menkir, A., Warburton, M.L., Windham, G.L. 2015. Identifying and developing maize germplasm with resistance to aflatoxin contamination. World Mycotoxin Journal. 8(2):193-209.

Interpretive Summary: Aflatoxin, produced by the fungus Aspergillus flavus, occurs naturally in corn. It is the most potent carcinogen found in nature; it is toxic to both humans and animals. Aflatoxin contamination was first recognized as a major problem associated with corn production in the southeastern U.S. in the 1970s. Aflatoxin contamination has remained a chronic problem in the Southeast. Plant resistance is generally considered a highly desirable strategy for reducing aflatoxin contamination in maize. Efforts to identify maize germplasm with resistance to A. flavus infection and aflatoxin contamination were initiated at several locations in the late 1970s and early 1980s. Lack of reliable field inoculation techniques, however, was a major impediment to success. Improved inoculation and evaluation techniques led to more successful identification of corn germplasm with resistance to A. flavus infection and aflatoxin contamination. Mp313E, a germplasm line developed in Mississippi and released in 1990, was the first line released as a source of resistance to A. flavus infection. A germplasm population, GT-MAS:gk, was created in Georgia by inter-mating progeny from kernels that were apparently not infected with A. flavus from a single ear of corn on which other kernels were infected. Four additional lines developed in Mississippi have been released as sources of resistance: Mp715, Mp717, Mp718, and Mp719 These lines were selected primarily from southern U.S. germplasm. GT601, GT602, and GT603 were developed from GT-MAS:gk and released as sources of resistance to aflatoxin. In a collaborative effort between the U. S. Department of Agriculture, Agricultural Research Service (USDA-ARS) and the International Institute for Tropical Agriculture (IITA), six tropical maize germplasm lines were released as sources of resistance to aflatoxin contamination in 2008. USDA-ARS research units at four locations in the southeastern U.S. are currently engaged in identification and development of maize germplasm with resistance to A. flavus infection and aflatoxin accumulation: (1) Plant Science Research Unit, Raleigh, NC; (2) Corn Host Plant Resistance Research Unit, Mississippi State, MS; (3) Crop Protection and Management Research Unit and Crop Genetics and Breeding Research Unit, Tifton, GA; and (4) Food and Feed Safety Research Unit, New Orleans, LA. Although specific research objectives pursued by the four research units differ, they share a common objective of eliminating a threat to food and feed safety and reducing economic losses associated with aflatoxin accumulation in corn grain.

Technical Abstract: Aflatoxin, produced by the fungus Aspergillus flavus, occurs naturally in maize, Zea mays L. It is the most potent carcinogen found in nature, and it is toxic to both humans and animals. Although first identified and recognized as a threat to animals when 100,000 turkeys died in England in 1961, aflatoxin is now recognized as a threat to other livestock, pets, and wildlife as well. Dietary exposure to aflatoxin is one of the major causes of hepatocellular carcinoma, the fifth most common cancer in humans worldwide. Its acute toxicity also poses a serious threat to humans in developing countries where maize is a dietary staple. Aflatoxin contamination was first recognized as a major problem associated with maize production in the southeastern U.S. in the 1970s. Aflatoxin contamination has remained a chronic problem in the Southeast. Plant resistance is generally considered a highly desirable strategy for reducing aflatoxin contamination in maize. Efforts to identify maize germplasm with resistance to A. flavus infection and aflatoxin contamination were initiated at several locations in the late 1970s and early 1980s . The lack of reliable field inoculation techniques, however, was a major impediment to success. Improved inoculation and evaluation techniques led to more successful identification of maize genotypes with resistance to A. flavus infection and aflatoxin contamination. Mp313E, a germplasm line developed in Mississippi, was the first line released as a source of resistance to A. flavus infection in 1990. A germplasm population, GT-MAS:gk, was created in Georgia by inter-mating progeny from kernels that were apparently not infected with A. flavus from a single ear of maize on which other kernels were infected. Four additional lines developed in Mississippi have been released as sources of resistance: Mp715, Mp717, Mp718, and Mp719 These lines were selected primarily from southern U.S. germplasm. GT601, GT602, and GT603 were developed from GT-MAS:gk and released as sources of resistance to aflatoxin. In a collaborative effort between the U. S. Department of Agriculture, Agricultural Research Service (USDA-ARS) and the International Institute for Tropical Agriculture (IITA), six tropical maize germplasm lines were released as sources of resistance to aflatoxin contamination in 2008. USDA-ARS research units at four locations in the southeastern U.S. are currently engaged in identification and development of maize germplasm with resistance to A. flavus infection and aflatoxin accumulation: (1) Plant Science Research Unit, Raleigh, NC; (2) Corn Host Plant Resistance Research Unit, Mississippi State, MS; (3) Crop Protection and Management Research Unit and Crop Genetics and Breeding Research Unit, Tifton, GA; and (4) Food and Feed Safety Research Unit, New Orleans, LA. Although specific research objectives pursued by the four research units differ, they share a common objective of eliminating a threat to food and feed safety and reducing economic losses associated with aflatoxin accumulation in maize grain. Recent contributions and accomplishments of the four research units are discussed.