Abstract

Groundnut (Arachis hypogaea) is an important income-generating crop in sub-Saharan Africa. Biotic factors affecting production include fungal infections caused by Aspergillus flavus and Aspergillus parasiticus leading to aflatoxin contamination. Resistant cultivars can be a potential cost-effective strategy and a feasible option to small scale farmers. This study aimed to compare the colonizing effect of the A. flavus and A. parasiticus and to evaluate the genetic resistance of selected groundnut varieties to A. flavus and parasiticus. The study was conducted at Zambia Agriculture Research Institute, Chilanga, Zambia. Intact, mature, and undamaged kernels of Natal common, Chishango and MGV4 were infected with A. flavus and A. parasiticus. The experiment followed a layout of 3 (groundnut genotypes) x 2 (Aspergillus isolates [A. flavus (S-strain) and A. parasiticus]) factorial experiment arranged in a completely randomized design, with three replications. Aflatoxin levels ranged from 0.12 to 0.24 µg/ kg in all groundnut genotypes inoculated with A. flavus  MGV4 was identified as the most resistant genotype exhibiting the lowest levels of aflatoxin content (0.12 µg/kg) (P<0.001). On the other hand, A. parasiticus was identified as a faster colonizing pathogen than A. flavus despite producing negligible amounts of aflatoxins in all evaluated groundnut genotypes.

Key words: Aspergillus species, aflatoxin levels, severity, incidence, seed infection.