Evaluation of Maize Inbred Lines for Resistance to Aspergillus and Fusarium Ear Rot and Mycotoxin Accumulation.

Mycotoxin contamination in corn grain is a worldwide threat to safety of both human food and animal feed.   A select group of inbred corn lines was evaluated in field trials for ear rot caused by Aspergillus flavus and Fusarium verticillioides and mycotoxin accumulation in grain.  Our goal was to identify lines resistant to both fungi.  In separate tests, 20 inbred lines were inoculated with either A. flavus or F. verticillioides.  After harvest, ears were rated for rot and evaluated for levels of aflatoxin or fumonisin contamination.  Inbred line Mp717 exhibits low grain aflatoxin contamination and it also had the lowest levels of fumonisin.  Inbred line Mp317 has been shown previously to have low levels of F. verticillioides kernel infection and fumonisin contamination.  Mp317 also had low levels of aflatoxin contamination in this study.   Area of the ear rotted by F. verticillioides and A. flavus was significantly correlated to toxin production for both fumonisin (p = 0.0002; r = 0.74) and aflatoxin (p = 0.004; r = 0.61), indicating that inbreds exhibiting aflatoxin resistance may also be good sources of fumonisin resistance. Our method of quantifying ear rot may also be used to rapidly screen lines for A. flavus resistance and subsequent aflatoxin accumulation in preliminary evaluations.