First author: Department of Plant Pathology and Department of Crop Science, North Carolina State University, Raleigh 27695-7620; second author: Department of Soil and Crop Sciences, Texas A&M University, College Station 77843-2474; third author: Department of Plant Pathology, North Carolina State University, Raleigh 27695-7567; fourth author: Department of Crop Sciences, University of Illinois, Urbana-Champaign 61801; fifth author: U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) National Center for Agricultural Utilization Research, Peoria, IL, 61604; sixth author: Department of Plant Pathology and Microbiology, Texas A&M University, College Station; seventh author: Pioneer Génétique, Pacé, France; and eighth author: USDA-ARS, Plant Science Research Unit, Department of Crop Science, North Carolina State University, Raleigh 27695-7620
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Accepted for publication 30 September 2006.
Fusarium verticillioides, F. proliferatum, and Aspergillus flavus cause ear rots of maize and contaminate the grain with mycotoxins (fumonisin or aflatoxin). The objective of this study was to investigate the relationships between resistance to Fusarium and Aspergillus ear rots and fumonisin and aflatoxin contamination. Based on a previous study of 143 recombinant inbred lines from the cross NC300 × B104, 24 lines with the highest and 24 lines with the lowest mean fumonisin concentration were selected for further evaluation. Paired plots of each line were inoculated with F. verticillioides and F. proliferatum or with A. flavus in replicated trials in 2004 and 2005 in Clayton, NC, and College Station, TX. The low-fumonisin group had significantly lower levels of fumonisin, aflatoxin, and Fusarium and Aspergillus ear rots. Across year-location environments, all four traits were significantly correlated; the genotypic correlation (rG) ranged from rG = 0.88 (aflatoxin and Aspergillus ear rot) to rG = 0.99 (Fusarium and Aspergillus ear rots). Quantitative trait loci (QTLs) were identified and their effects estimated. Two QTLs affected both toxin concentrations, one QTL affected both ear rots, and one QTL affected Aspergillus and Fusarium rots and fumonisin. These results suggest that at least some of the genes involved in resistance to ear rots and mycotoxin contamination are identical or genetically linked.
The American Phytopathological Society, 2007