Study of Pathogenicity variation of Fusarium verticillioides isolates, causal agent of corn ear rot in field and greenhouse trials

Fusarium ear rot is the most important disease of corn in Iran. In this research with the purpose of studying the casual agent, some infected ears of corn were collected from fields of Esfahan, Sari, Kermanshah and Karaj. A total of 40 Fusarium isolates were identified after isolation and purification. According to valid mycological key references based on the different morphological characters and some physiological traits, 32 Fusarium verticillioides and 8 Fusarium proliferatum isolates were identified. In order to evaluate the pathogenicity variation of 22 Fusarium verticillioides isolates on susceptible maize line (MO17), the causal agents of Fusarium ear rot of corn, an experiment based on a randomized complete block design (RCBD) with 24 treatments (The treatment were consisted of 22 F. verticillioides isolates, one control with sterile distilled water inoculation, and one control without inoculation) and three replications were conducted in greenhouse and field. The results of the analysis of variance of data showed that difference between treatments were statistically significant. Totally, three isolates (4 and 6 from Karaj, 20 from Sari) of Fusarium verticillioides showed the highest level of virulence among all 22 isolates in greenhouse. Totally, two isolates (14, 18 from Sari) of Fusarium verticillioides showed the highest level of virulence among all 22 isolates in field.