Evaluation of Sampling Methods for Detecting Aflatoxin Contamination in Small Test Plots of Maize Inoculated With Aspergillus flavus

Abstract

AbstractTwo commercial maize (Zea mays L.) hybrids were grown in 1978 and 1980 to evaluate 13 sampling methods (grain‐sampling‐inoculation combinations) for formation of aflatoxin by Aspergillus flavus Link. The effectiveness of each method in producing uniform, consistent, genotype‐differentiating levels of aflatoxin was determined. Differences in level of aflatoxin contamination did not occur between years, but were highly significant between hybrids and among evaluation methods. Interactions among years, hybrids, and evaluation methods were nonsignificant. Mid‐ear inoculations with a knife at 20 d after full silk were more effective than were needle inoculations at the ear‐tip in eliciting high and consistent aflatoxin levels. Kernels from the immediate inoculated area of the ear or from inoculated segments of ears had the highest levels of aflatoxin contamination. Kernels from entire ears, or portions of ears, that appeared clean of fungus infection contained lower levels of aflatoxin contamination. Kernels from entire ears contained low to intermediate levels of aflatoxin, but the differences in levels seem adequate for detecting differences between genotypes. Treatments with low aflatoxin levels were generally associated with the highest coefficients of variation, although variances per se could not be positively associated with aflatoxin concentrations of the various methods.