Evaluation of the Phenol Production Potential in Maize (Zea mays L.) in Response to Infection Caused by Fusariun verticillioides (Niren.)

This study investigated phenol production in five maize varieties in response to infection caused by Fusarium verticillioides. Pure culture of the pathogen was obtained from Plant Pathology Laboratory of the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. The screen house experiment was laid out in a completely randomized design. Dual inoculation was done where soil was infected separately before planting and seedlings were infected separately two weeks after planting with two volumes (10ml and 20ml) containing 1.4×107 spores/ml suspension of F. verticillioides. The maize plants were harvested at 4th, 5th and 6th weeks after inoculation and the maize plants were dried at room temperature before determination of phenol content in each of the varieties. Data gathered on the agronomic parameters and phenol contents were subjected to analysis of variance (ANOVA) using SAS 9.1 statistical package.

All the maize varieties recorded more than 70% stalk rot incidence while the severity ranged from 19.01% in variety ART-98-SW1 to 25.21% in ART-98-SW6. ART-98-SW6 showed the most (p<0.05) phenol content (21.28 mg/g). Soil inoculation produced the highest percentage stalk rot severity while seedling inoculation showed significantly higher phenol contents across the period of study. Similarly, disease severity increased with increasing inoculum levels with highest attained using 20 ml (23.99%) while higher phenol content was obtained at inoculum level 10 ml (18.61 mg/g) compared to results using 20 ml (15.63 mg/g) and control (7.88 mg/g). The maize variety; ART-98-SW6 with highest stalk rot severity also produced the highest phenol content. Overall, the rate of phenol production in maize corresponded with the extent of severity F. verticillioides infections.