MOLECULAR CHARACTERIZATION AND PATHOGENICITY OF Fusarium falciforme CAUSING WILT IN THREE IMPORTANT LEGUMES CROPS IN NIGERIA

Abstract

Legumes, members of the Fabaceae family are susceptible to fungal pathogens causing wilts and root rots. This study aimed to examine the distribution and virulence of Fusarium wilt isolates on three legume crops: cowpea (Vigna unguiculata L.), soybean (Glycine max L.), and African yam bean (AYB, Sphenostylis stenocarpa H.). The investigation also sought to establish a relationship between Fusarium strains and their ability to infect various legume crops. Infected and withered roots were collected from three fields at the International Institute of Tropical Agriculture, Ibadan and isolated on Potato Dextrose Agar medium plates for identification. Pathogenicity test to show the relationship between Fusarium falciforme on the legume crops were investigated in a screen house experiment using completely randomized design (CRD). Each seedling 6 was inoculated with 30 ml of F. falciforme suspension (5 x10 conidia ml). Data collected over 5 to 25 days after inoculation were analyzed using analysis of variance at 5% probability. All isolates were identified as F. falciforme through conventional and molecular characterization. To our knowledge this is the first report of Fusarium wilt in legumes caused by F. falciforme in Nigeria. The results indicated significant differences (p ≤0.05) among the treatments applied to the crops, treatment effects were significant (p ≤0.05) with AYB showing a notable difference compared to cowpea and soybean. This study showed that F. falciforme from AYB showed high level of virulence compared to strains from cowpea and soybean, and that AYB is resistance to F. falciforme strains from the other two crops.