Aflatoxin Production in Aspergillus flavus Inoculated Ears of Corn Grown at Diverse Locations
1975
Lillehoj, E. B. | Kwolek, W. F. | Vandegraft, E. E. | Zuber, M. S. | Calvert, O. H. | Widstrom, N. | Futrell, M. C. | Bockholt, A. J.
Normal and opaque-2 endosperm counterparts of two Zea mays L. hybrids were grown during 1973 at locations in Illinois, Missouri, Georgia, and Texas; 20 days after silking test ears were inoculated with Aspergillus flavus Link ex Fr. spores. Other ears were mechanically damaged or untreated. Sample ears were harvested 15, 30, 45, and 70 days after treatment. After shelling the corn was ground, examined for bright-greenish yellow (BGY) fluorescence, and assayed for aflatoxin. The number of aflatoxin-positives in 128 inoculated ears/plot increased generally from North to South: Illinois, 28; Missouri, 86; Texas, 111; and Georgia, 117. The mean levels of aflatoxin B₁ in toxin-contaminated ears showed a similar geographical pattern: Illinois, 2.4 ppb; Missouri, 22.5 ppb; Texas, 114.5 ppb; and Georgia, 133.9 ppb. Almost all the toxin production occurred during the initial 30 days after inoculation. Fewer toxin-contaminated ears were found in the doublecross hybrid than in the single cross, but no significant difference in aflatoxin incidence was observed between endosperm types (normal vs. opaque). Sixty of 512 damaged uninoenlated ears and 21 of 512 untreated control ears contained aflatoxin; 80% of the aflatoxin-positives associated with physically damaged or control ears were observed in corn from the Georgia location.
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