Sources of Resistance in Maize to Kernel Infection by Aspergillus flavus in the Field

Abstract

Infection of maize, Zea mays L., kernels by Aspergillus flavus Link ex Fr. and subsequent aflatoxin production can be an extremely serious problem; especially in maize grown in the southeastern part of the USA. Maize genotypes that resist attack by this fungus are desperately needed. The objective of these studies was to identify maize inbreds with resistance to kernel infection by A. flavus. Inbreds were inoculated with a pinbar and evaluated for percentage of kernels internally infected by this fungus. Nearly a 5‐fold difference (6 to 30%) among the inbreds tested over a 2‐yr period was found. Five of the inbreds selected as resistant, and five as susceptible, were subsequently tested using a pinbar and two needle inoculation techniques. The pinbar inoculation technique gave the highest level of kernel infection and the greatest separation of the inbreds into their previously classified groups, but all methods of inoculation showed that the two groups of inbreds differed significantly from each other. In a test with 50 inbreds inoculated by the side‐needle inoculation technique, percentage of A. flavus infected kernels ranged from 4 to 62. Resistant (Mp313E, SC54, and Mo18W) and susceptible (T202, T216, and SC212M) inbreds averaged 10 and 44% infected kernels, respectively.