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Postharvest Pathology and Mycotoxins

Genotypic Differences in Reaction of Stored Corn Kernels to Attack by Selected Aspergillus and Penicillium spp.. F. A. Cantone, Graduate student, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907; J. Tuite(2), L. F. Bauman(3), and R. Stroshine(4). (2)Professor, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907; (3)Professor, Department of Agronomy, Purdue University, West Lafayette, IN 47907; (4)Assistant professor, Department of Agricultural Engineering, Purdue University, West Lafayette, IN 47907. Phytopathology 73:1250-1255. Accepted for publication 24 March 1983. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-1250.

Hand-harvested and hand-shelled kernels of corn inbreds and hybrids commonly grown in the midwest were evaluated in storage for their reactions to invasion by Aspergillus species from the taxonomic groups of A. glaucus and A. flavus, and by Penicillium species. Genotypes were separately inoculated with each group of fungi and stored at three temperatures (26, 30, and 12 C) and relative humidities (85, 91, and 88%), respectively. Percentage of kernel infection, seed germination, and visible mold, number of fungal propagules, and ergosterol concentration were the criteria used to detect resistance and susceptibility. The estimation of visible mold on the kernels was an easy and generally effective way to screen for resistant and susceptible genotypes. The number of propagules and the concentration of ergosterol were useful quantitations of the amount of fungi in and on the corn kernels. Linear correlations between visible mold, fungal propagules, and ergosterol were generally high. Because kernels were rapidly infected and usually retained high germination, kernel infection and seed germination were inadequate for detecting resistance to mold development, although seed germination and number of propagules in the test with A. flavus exhibited a highly inverse relationship. Overall, the genotypes responded similarly to attack by all three fungal groups. Consistently high and low levels of susceptibility to growth and sporulation of the fungi were exhibited by kernels of H95 and B73 x Mo17, respectively. Variations occurred with some of the intermediate genotypes. Some genotypes, including H95 and B73 x Mo17, were also consistent in reactions to attack by Penicillium over two crop years. Thus, it appears that inherent and relatively consistent differences in susceptibility to the main groups of storage fungi exist among corn genotypes.