Morphological and Molecular Characterization of Fusarium Isolates from Morphological and Molecular Characterization of Fusarium Isolates from Lakatan Banana Plantations of Tampakan, South Cotabato

Fusarium wilt (FW) poses a significant threat to the banana industry. In Tampakan, South Cotabato, bananas account for 40% of the annual income of the municipality, and are considered an essential food source for the people. In this study, a geographical map of the Fusarium-infected Lakatan banana plantation was generated and the Fusarium pathogen infecting the plantations were characterized culturally, morphologically and biochemically. Out of the 11 Fusarium suspected banana sample tissues collected, only 5 tissue samples tested positive for FW caused by Fusarium oxysporum f. sp. cubense (Foc) using Quantitative real-time Polymerase Chain Reaction (PCR). Three (3) barangays in Tampakan have confirmed cases of Fusarium. The banana tissue samples from Brgy. Danlag (D1.1) and Brgy. Pulabato (P1.2) tested positive for Foc in its early stages of infection, while other samples from Brgy. Lambayong (L1, L2, and L3) tested positive for Foc infection in its advanced stage. Fusarium isolates from L1, L2, and L3 that tested positive in qPCR for Foc developed white cottony colonies on potato dextrose agar after 1 week incubation, while fungal colonies from D1.2 and P.1.1 did not show the same morphological characteristics after 7 days of inoculation in Potato Dextrose Agar (PDA) having smaller mycelial growth even after 9 days of incubation. Of the 5 putative Foc isolates only fungal isolates L1, L2, and L3 exhibited similar colonial and morphological characteristics as the reference Fusarium isolate having white aerial colonies and white pigmentation on PDA 2 weeks post inoculation with distinct appearance of conidia and chlamydospores. Molecular analysis revealed significant alignments of D1.2 and P1.1 with Fusarium oxysporum as confirmed by the Maximum Likelihood method.