Abstract

The Aspergillus flavus infection of peanut (Arachis hypogaea) results in the accumulation of aflatoxins in seeds, which are very harmful to humans and animals. Mutation breeding programs are an effective way of inducing resistant mutants. In this study, we induced a genetic variation by using ethyl methanesulfonate (EMS) and gamma rays treatment for four peanut cultivars (32 mutants from Giza 6, 22 mutants from Gregory, 15 mutants from Giza 4 and 15 mutants from Giza 5). The resistant mutants for A. flavus were identified by analyzing β-1-3-glucanases activities of the controls and infected mutants using polyacrylamide gel electrophoresis (PAGE). Two, four and four mutants derived from Giza 6, Gregory and Giza 4, respectively, showed high activities of β-1-3-glucanases and therefore more resistant to the infection of A. flavus. The genetic similarity of these mutants and their controls was also tested using random amplified polymorphic DNA (RAPD) approach. Although natural polymorphism among peanut cultivars was very low, RAPD patterns showed high polymorphism percentage of DNA fragments (37.13%).

Key words: Aspergillus flavus, aflatoxins, Arachis hypogaea, peanut, gamma rays, ethyl methanesulfonate (EMS), pathogenesis related (PR) proteins.