Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2007
Publication Date: January 1, 2008
Citation: Williams, W.P., Windham, G.L., Buckley, P.M. 2008. Diallel analysis of aflatoxin accumulation in maize. Crop Science. 48:134-138. Interpretive Summary: Aflatoxin, produced by the fungus Aspergillus flavus, is a potent carcinogen. Its presence in corn reduces marketability. Corn produced in the southern USA is especially vulnerable to aflatoxin contamination. Corn germplasm lines with genetic resistance to aflatoxin have been developed and released by USDA-ARS at Mississippi State. All possible crosses were made among four aflatoxin-resistant lines and six additional inbred lines. The resulting hybrids were evaluated for resistance to aflatoxin contamination in field tests conducted in 2005 and 2006. A diallel analysis indicated that the four aflatoxin-resistant lines, Mp313E, Mp494, Mp715, and Mp717, exhibited excellent general combining ability for reduced aflatoxin contamination. Two other lines, Mo18W and NC408, also exhibited significant general combining ability for reduced aflatoxin contamination. These lines should be useful in development aflatoxin-resistant corn hybrids for the southern USA.
Technical Abstract: Aflatoxin, a toxin produced by the fungus Aspergillus flavus Link: Fries, occurs naturally in maize, Zea mays L. It is a potent carcinogen, and its presence markedly reduces the value of grain. Host plant resistance to A. flavus infection and subsequent aflatoxin accumulation is generally considered a desirable means of reducing losses to aflatoxin. Maize germplasm lines with resistance to aflatoxin contamination have been developed in Mississippi. Four of the aflatoxin-resistant lines and six other lines were used as parents to produce a diallel cross. The diallel cross was evaluated for resistance to aflatoxin contamination in field trials conducted in Mississippi in 2005 and 2006. General (GCA) and specific (SCA) combining ability were highly significant sources of variation. Reciprocal effects were not significant. Estimated GCA effects for reduced aflatoxin were highly significant for the four lines developed as sources of resistance, Mp313E, Mp494, Mp715, and Mp717. The GCA effect for reduced aflatoxin was also highly significant for Mo18W and NC408. These lines should be useful in developing maize lines and hybrids with resistance to aflatoxin contamination. Breeding methods that maximize the use of GCA should be effective.