Growth and Toxigenicity of A. flavus on Resistant and Susceptible Peanut Genotypes.

Abstract

Aflatoxin contamination poses serious health concerns to consumers of peanut and peanut products. This study aimed at investigating the response of peanuts to Aspergillus flavus infection and aflatoxin accumulation. Isolates of A. flavus were characterised either as aflatoxigenic or non-aflatoxigenic using multiple cultural techniques. The selected isolates were used in an in vitro seed colonisation (IVSC) experiment on two A. flavus-resistant and susceptible peanut genotypes. Disease incidence, severity, and aflatoxin accumulation were measured. Genotypes differed significantly (p < 0.001) in terms of the incidence and severity of aflatoxigenic and non-aflatoxigenic A. flavus infection with the non-aflatoxigenic isolate having significantly higher incidence and severity values. There was no accumulation of aflatoxins in peanut genotypes inoculated with non-aflatoxigenic isolate, indicating its potential as a biocontrol agent. Inoculations with the aflatoxigenic isolate resulted in the accumulation of aflatoxin B1 and G1 in all the peanut genotypes. Aflatoxin B2 was not detected in ICGV–03401 (resistant genotype), while it was present and higher in Manipinta (susceptible genotype) than L027B (resistant genotype). ICGV–03401 can resist fungal infection and aflatoxin accumulation than L027B and Manipinta. Non-aflatoxigenic isolate detected in this study could further be investigated as a biocontrol agent.