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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 #316613

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

Location: Corn Host Plant Resistance Research

Title: Aflatoxin accumulation in a maize diallel cross

Author
item Williams, William
item Windham, Gary

Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2015
Publication Date: 6/17/2015
Citation: Williams, W.P., Windham, G.L. 2015. Aflatoxin accumulation in a maize diallel cross. Agriculture. 5:344-353; doi:10.3390/agriculture5020344.

Interpretive Summary: Aflatoxins, produced by the fungus Aspergillus flavus, occur naturally in corn. Dietary exposure to aflatoxins is one of the major causes of hepatocellular carcinoma in humans; however, aflatoxins are toxic not only to humans, but also wildlife, livestock, and pets. Plant resistance is generally considered a highly desirable approach to reduction or elimination of aflatoxin in corn grain. USDA-ARS scientists located at Mississippi State University have identified and released maize germplasm lines that have resistance to aflatoxin accumulation. In this investigation a diallel cross was produced by crossing 10 inbred lines with varying degrees of resistance/susceptibility in all possible combinations. Three lines that had been developed at Mississippi State and released as sources of resistance to aflatoxin accumulation were included as parents of the diallel cross. The parents and the 45 single crosses making up the diallel cross were evaluated for aflatoxin accumulation in field tests conducted at Mississippi State in 2013 and 2014. The parental inbred lines Mp717, Mp313E, and Mp719 exhibited low levels of aflatoxin accumulation. These lines should be especially useful in developing corn hybrids with resistance to aflatoxin accumulation.

Technical Abstract: Aflatoxins, produced by the fungus Aspergillus flavus, occur naturally in maize. Contamination of maize grain with aflatoxin is a major food and feed safety problem and greatly reduces the value of the grain. Plant resistance is generally considered a highly desirable approach to reduction or elimination of aflatoxin in maize grain. In this investigation a diallel cross was produced by crossing 10 inbred lines with varying degrees of resistance to aflatoxin accumulation in all possible combinations. Three lines that had been developed and released as sources of resistance to aflatoxin accumulation were included as parents. The 10 parental inbred lines and the 45 single crosses making up the diallel cross were evaluated for aflatoxin accumulation in field tests conducted in 2013 and 2014. Plants were inoculated with an A. flavus spore suspension 7 days after silk emergence. Ears were harvested approximately 60 days later and concentration of aflatoxin in the grain determined. The parental inbred lines Mp717, Mp313E, and Mp719 exhibited low levels (3-12 ng/g) of aflatoxin accumulation. In the diallel analysis, both general and specific combining ability were significant sources of variation in the inheritance of resistance to aflatoxin accumulation. General combining ability effects for reduced aflatoxin accumulation were greatest for Mp494, Mp719, and Mp717. These lines should be especially useful in breeding for resistance to aflatoxin accumulation. Breeding strategies such as reciprocal recurrent selection would be appropriate.