Effects of Genotype and Date of Harvest on Infection of Peanut Seed by Aspergillus flavus and Subsequent Contamination with Aflatoxin1

Abstract

Abstract Several peanut genotypes reported as resistant, susceptible or highly susceptible to in vitro colonization of rehydrated, mature, stored, undamaged seed by Aspergillus flavus (IVSCAF) were tested for natural seed infection by A. flavus and other fungi in two or more replicated field trials at ICRISAT Center, Patancheru, India, in 1979–1984. Undamaged pods were sampled before maturity, at optimum maturity (normal harvest) and when over - mature (late harvest) and seed examined for infection by A. flavus and other fungi. In the 1983 and 1984 rainy and 1983/84 postrainy seasons, only four genotypes (one resistant and three susceptible) were tested, and seed were also tested for aflatoxin content. In all seasons the genotypes reported as IVSCAF - resistant had significantly lower levels of seed infection with A. flavus and other fungi than did genotypes reported as IVSCAF - susceptible. Cenotypic differences in levels of seed infection by A. flavus were consistent over seasons. The resistant cultivar J11 had a significantly lower aflatoxin content than the other three IVSCAF - susceptible genotypes tested in the 1983–1984 seasons. Drought stress in the 1984 season apparently increased susceptibility to seed infection by A. flavus and other fungi, and to aflatoxin contamination, in all cultivars. Seed infection by A. flavus and other fungi, and aflatoxin contamination increased with increasing maturity of pods, indicating the importance of lifting the peanut crop at optimum maturity.