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United States Department of Agriculture

Agricultural Research Service

Research Project: GENETIC AND GENOMIC APPROACHES TO IMPROVE PEANUT AND CORN RESISTANCE TO DISEASE AND AFLATOXIN CONTAMINATION Title: Inoculation Techniques in the Field Screening and Selection for Corn Inbred and Hybirds Resistance to Preharvest Aflatoxin Contamination

Authors
item Guo, Baozhu
item Krakowsky, Matthew
item Ni, Xinzhi
item Wilson, Jeffrey
item Abbas, Hamed
item Kemerait, Robert -
item Lee, Dewey -
item Scully, Brian
item Henry, William

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 27, 2009
Publication Date: October 27, 2009
Citation: Guo, B. Krakowsky, M. Ni, X. Wilson, J.P. Abbas, H.K. Kemerait, R. Lee, D. Scully, B. Henry W.B. 2009. Innoculation Techniques in the Field Screening and Selection for Corn Inbred and Hybirds Resistance to Preharvest Aflatoxin Contamination. Presented at the Mississippi State University on Reducing Aflatoxin Contamination in Corn meeting, October 27-28, 2009.

Technical Abstract: Preharvest aflatoxin contamination of grain grown on the U.S. Southeastern Coast Plain is provoked and aggravated by both biotic and abiotic stress factors that influence infection by Asperigillus flavus. An array of arthropod species contribute to the dispersal of this fungus as they attack and feed on the developing grain. Inoculation techniques that minimally injury kernels such as the knife and side-needle work best in environments typically favorable to fungal growth and aflatoxin accumulation. Among the techniques that entail kernel wounding the pinbar provides an effective way to discriminate among corn breeding lines and germplasm, but this technique has the disadvantage of damaging a large number of kernels. Seven methods including three kernel wounding techniques were evaluated for effectiveness of inducing aflatoxin accumulation. The three kernel wounding techniques including the pinbar, knife and side-needle were associated with significantly higher levels of aflatoxin contamination. The knife and side-needle methods are more conducive to field inoculations than the pinbar, and the use of one or both is recommended for field evaluations of aflatoxin accumulation in corn. Other non-wounding methods are inconsistient on the Coastal Plain. Since 1996, selection within the GT-MAS:gk population has yielded a number of adapted and resistant inbreds. Recently, two inbred lines, GT601 (AM-1) (PI 644026) and GT602 (AM-2) (PI 644027) were selected and released. We also screened 87 inbred and breeding lines in 2005 and 2006 and analyzed the levels of total aflatoxin and fumonisin B1. A correlation between total aflatoxin and fumonisin B1 in each line was not evident. Nonetheless, these data suggested that the genetic resistance is evident and not correlated to both fungi, and demonstrate that exposure to both mycotoxins can occur simultaneously. The field screening research is complimented and enhanced by molecular techniques that have proven invaluable in the identification and development of superior germplasm, inbreds and hybrids.

Last Modified: 10/30/2014