Morphological and Molecular Characterisation of Fusarium Wilt Pathogen Isolated from Sunhemp

Abstract

Fusarium wilt, caused by Fusarium oxysporum f. sp. crotalariae (Kulkarni) Subram. is a significant disease affecting sunhemp (Crotalaria juncea) production, leading to substantial yield losses. To understand the pathogen's biology and enhance management strategies, comprehensive investigations were conducted under laboratory and field conditions at the University of Agricultural Sciences, Dharwad, during 2019-20. The pathogen was cultured on various solid media, with Richard’s agar identified as the most conducive for fungal growth, while potato dextrose agar, Czapeck’s dox agar, and Richard’s agar facilitated good sporulation. Notable variation was observed in colony morphology, including color, texture, margin, growth nature, and sporulation across the different media. Molecular characterization confirmed the pathogen as closely related to F. udum, with a 99.79% similarity to an isolate with the GenBank accession number MK575503.1. These findings provide valuable insights into the pathogen's growth characteristics and genetic identity.