Importance, Fumonisin production and aggressiveness of Gibberella fujikuroi complex recovered from maize in northwestern Argentina

Abstract

Mating population, in vitro fumonisin production and aggressiveness of maize isolates belonging to the Gibberella fujikuroi complex were assessed in corn producing area of northwestern Argentina. Mating population A (F. verticillioides) was the most prevalent species (53%) coexisting with some isolates belonging to MAT-D (F. proliferatum) 29% and MAT-E (F. subglutinans) 18%. Fumonisin production varied from 4000 to 7457 ųg/kg (ppb) for MAT-A and from 0,1 - 0,54 a ųg/kg for MAT-E. The isolates belonging to MAT-D produced undetectable levels. All isolates caused more disease severity to the most susceptible hybrid in comparison to that of the two moderately resistant hybrids regardless of the fungal species, in most environments, but with no effect for the interaction hybrid x isolate. Results indicate that these three Fusarium spp. coexist in the region, with low environmental specialization to cause ear rots, with potential to contaminate the grain with fumonisins and that, broad resistance mechanisms effective across prevalent local fungal species might exist. The information obtained in the present work represents a first step for the region under study and it will help to determine the importance of this disease, and to delineate management strategies within the framework of sustainable agriculture.