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International Journal of Agronomy
Volume 2013 (2013), Article ID 972316, 6 pages
http://dx.doi.org/10.1155/2013/972316
Research Article

Comparison of Two Inoculation Methods for Evaluating Maize for Resistance to Aspergillus flavus Infection and Aflatoxin Accumulation

1USDA-ARS Corn Host Plant Resistance Research Unit, P.O. Box 9555, Mississippi State, MS 39762, USA
2Plant and Soil Sciences Department, Mississippi State University, P.O. Box 9555, Mississippi State, MS 39762, USA

Received 29 April 2013; Revised 20 October 2013; Accepted 20 October 2013

Academic Editor: Robert J. Kremer

Copyright © 2013 W. Paul Williams et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Aflatoxin, the most potent carcinogen found in nature, is produced by the fungus Aspergillus flavus and occurs naturally in maize, Zea mays L. Growing maize hybrids with genetic resistance to aflatoxin contamination are generally considered a highly desirable way to reduce losses to aflatoxin. Developing resistant hybrids requires reliable inoculation methods for screening maize germplasm for resistance to A. flavus infection and aflatoxin accumulation. The side-needle technique is a widely used inoculation technique: an A. flavus conidial suspension is injected underneath the husks into the side of the ear. This wounds the ear and limits expression of resistance associated with husk coverage, pericarp thickness, and seed coat integrity. In this investigation, the side-needle technique was compared with a second inoculation method that involved dispensing wheat kernels infected with A. flavus into plant whorls at 35 and 49 days after planting. Results showed that although the side-needle technique produced higher levels of aflatoxin accumulation, differences in A. flavus biomass produced by the two inoculation techniques were not significant. Both inoculation techniques were effective in differentiating resistant and susceptible single cross hybrids irrespective of the use of A. flavus infection or aflatoxin accumulation as a basis to define resistance.