Heritabilities and correlations of fusarium ear rot resistance and fumonisin contamination resistance in two maize populations

Fusarium verticillioides (Sacc.) Nirenberg (synonym E moniliforme Sheldon) (teleomorph: Gibberella moniliformis) and E proliferatum (Matsushima) Nirenberg (teleomorph: G. intermedia) are fungal pathogens of maize (Zea mays L.) that cause ear rot and contaminate grain with fumonisins, a family of mycotoxins that adversely affect animal and human health. The objective of this study was to estimate heritabilities of and genotypic and phenotypic correlations between fumonisin concentration, ear rot, and flowering time in two maize populations. In the (GE440 X FR1064) X FR1064 backcross population, the genotypic and phenotypic correlations between ear rot and fumonisin concentration were 0.96 and 0.40, respectively. Heritability estimated on an entry mean basis was 0.75 for fumonisin concentration and 0.47 for ear rot resistance. In the NC300 X B104 recombinant inbred line population, the genotypic and phenotypic correlations between ear rot and fumonisin concentration were 0.87 and 0.64, respectively. Heritability estimated on an entry mean basis was 0.86 for fumonisin concentration and 0.80 for ear rot resistance. Correlations between fumonisin concentration and silking date were not significant in either population, and correlations between ear rot resistance and silking date were small (less than 0.30) in both populations. Moderate to high heritabilities and strong genetic correlations between ear rot and fumonisin concentration suggest that selection for reduced ear rot should frequently identify lines with reduced fumonisin concentration. Ear rot can be screened visually and so is less costly and less time-consuming to evaluate than laboratory assays for fumonisin concentration.