Field Evaluation of Peanut Genotypes for Resistance to Infection by Aspergillus parasiticus1,2

Abstract

Abstract Fourteen peanut genotypes (Arachis hypogaea) were evaluated for resistance to Aspergillus parasiticus infection in 1983 and 1984 in rain-shaded field microplots where water stress conditions were simulated, and in unshaded microplots under normal rainfall conditions. A brown color mutant of A. parasiticus (ATCC 24690) was grown on cracked corn and the colonized corn was spread on the soil in each microplot. Soil moisture and soil and air temperature were monitored. Infection of peanut pegs, pods, kernels and tap and fibrous roots was enhanced by low soil moisture. Infection of kernels differed among genotypes; all other tissues were found to be infected at moderate to high frequency and no genotype differences were observed. Genotypes J-11 and Lampang were characterized as resistant to A. parasiticus under both dry (1983) and moist (1984) field conditions. Although percentage infection of kernels varied with genotype, ranking of genotypes reported to have drought resistance was consistent under both dry and moist field conditions. Thirty-four peanut genotypes, including those tested in field microplots, were also evaluated for dry seed resistance to A. parasiticus infection in the laboratory. Genotype J-11 and PI 337409 were highly resistant. Except for J-11, there was no correlation between genotype rankings for resistance to dry seed infection and resistance under field conditions.