Effect of disease severity on yield and grain fumonisin concentration of maize hybrids inoculated with Fusarium verticillioides

Fusarium verticillioides causes Fusarium ear rot in maize (Zea mays L.) and contaminates grain with fumonisins, but there is little information on how the disease affects yield. Three hybrids were evaluated in conditions of natural infection and after silk inoculation with this fungus. Disease severity (percentage of the ear covered by mold) was assessed on a visual scale. In the inoculated treatment, ears within experimental units were grouped according to their disease severity rating. Grain weight and fumonisin concentration (ELISA) were assessed in each group. Relationships of disease severity with yield and with grain fumonisin concentration were mainly explained by linear models. Slopes varied from −0.6 to −2.0 g plant−1 per unit of disease severity for yield and from 3.4 to 10.9 μg g−1 per unit of disease severity for grain fumonisin concentration, depending on the hybrid and year. Linear responses suggested that losses of yield and grain quality might be reduced by using the most resistant hybrids exhibiting low frequencies of severely diseased ears.