Submitted to: American Phytopathogical Society Southern Division
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2001
Publication Date: 1/1/2002
Citation: Guo, B., Butron, A., Widstrom, N.W., Wilson, D.M., Snook, M.E., Lynch, R.E. 2002. Identification of maize chromosome regions associated with silk antibiotic compounds, husk coverage, and alfatoxin formation [abstract]. Phytopathology. 92:S149. Interpretive Summary:
Technical Abstract: The effect of husk tightness and coverage, subsequently has an important influence on aflatoxin contamination, especially as it relates to prevention of entry by insects into the ears of southern grown hybrids. Maysin and related compounds, such as apimaysin, 3'-methoxymaysin, and chlorogenic acid, have been determined to be important antibiotic compounds against corn earworm, but, to be effective under field conditions, silk antibiotics should be accompanied by a good husk coverage. Evaluation of genotypes inoculated with Aspergillus flavus and infested with corn earworm revealed that corn earworm injury and aflatoxin contamination of maize grain are consistently correlated when ear-feeding insects and A. flavus spores are abundant in the environment. Genetic mapping of the cross GT-A1 x GT119 (inbreds differing for resistance traits) was conducted and DNA genotyping was performed on 250 F2 plants using 112 RFLP probes and 6 restriction enzymes. Phenotypic trait measurements were made on F2:3 families in a replicated experiment in 1999 and 2000. A major QTL for maysin was identified on chromosome 1S, and QTLs for husk tightness were located on chromosomes 4L and 7S. The recombination of progenies with chromosome region 1S from GT-A1 and 2L from GT119 gave the lowest aflatoxin concentrations.