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Published Articles from USDA ARS National Program 108: Food Safety
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Title: Comparison of inoculation methods for evaluating maize for resistance to Aspergillus flavus infection and aflatoxin accumulation
Authors: Williams WP, Alpe M, Windham GL, Ozkan S, Mylroie JE
Journal: Int J Agron
Accepted date: 2013 Oct 10
Interpretive summary: Aflatoxin, causes cancer in humans and is toxic to livestock, pets, and wildlife. It is produced by the fungus Aspergillus flavus and is found corn, peanuts, and other crops. Growing corn hybrids with genetic resistance to aflatoxin contamination is generally considered a highly desirable way to reduce losses to aflatoxin. Developing resistant hybrids requires reliable inoculation methods to screen corn germplasm for resistance to A. flavus infection and aflatoxin accumulation. A technique using a tree marking gun to inject an A. flavus conidial suspension underneath the husks into the side of the ear was developed by USDA-ARS scientists at Mississippi State 25 years ago and is still widely used. This technique, referred to as the side-needle technique, physically wounds the ear of corn and bypasses some potential mechanisms of resistance such as good husk coverage. It is also labor intensive. In the current study a second inoculation method which involves placement of wheat kernels infected with A. flavus into plant whorls at 35 and 49 days after planting was evaluated and compared with the side-needle technique for two years. Results showed that although the side-needle technique produced higher levels of aflatoxin accumulation, the difference in A. flavus biomass produced by the two inoculation techniques was 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. This technique will be useful in breeding corn hybrids with resistance to aflatoxin accumulation.
Publication date: 2013 Oct
Pages: Art ID: 972316