Evaluation of greenhouse and field aggressiveness of Fusarium verticillioides from corn in Laguna province, Philippines

Fusarium verticillioides is one of economically important pathogens of corn worldwide. Sixteen isolates of F. verticillioides from Laguna province, Philippines were tested for aggressiveness expressed as total and main lesion length on 'Super Sweet' corn IPB variety 1 under field conditions across two trials using the toothpick inoculation method. Furthermore, other aggressiveness traits such as inhibition of seedling emergence, decrease of seedling height, fresh and dry weight were also determined in two greenhouse trials. All isolates were pathogenic to corn seedlings and mature plants compared to non-inoculated control. Significant genotypic variation was observed (P = 0.01) in trial and isolate-trial interaction for all traits across two greenhouse trials and that aggressiveness was highly influenced by the trial conditions. High correlation was found between seedling height, fresh weight, and dry weight results (r = 0.81, 0.83 and 0.74, respectively) and germination percentages. Correlation between greenhouse and field aggressiveness is moderate (r =-0.40). Implications of these findings in the population genetics of F. verticillioides and resistance breeding are discussed.