Patho-Ecological Distribution and Genetic Diversity of Fusarium oxysporum f. sp. cubense in Malbhog Banana Belts of India

Fusarium wilt, caused by Fusarium oxysporum f.sp. cubense (Foc), is recognized as one of the most devastating diseases affecting banana cultivation worldwide. In India, Foc extensively affects the Malbhog banana (AAB genomic group) production. In this study, we isolated 25 Foc isolates from wilt-affected Malbhog plantations of India. Pathogenicity test confirmed the identity of these isolates as Foc, the primary causative agent of wilt in banana. Morpho-cultural characterization of the Foc isolates showed large variation in colony morphological features, intensity, and pattern of pigmentation, chlamydospores, and conidial size. The molecular identification of these isolates using Race-1 and Race-4 specific primers established their identity as Race- 1 of Foc, with absence of TR- 4. For a more comprehensive understanding of genetic diversity of Foc isolates, we em-ployed ISSR molecular typing which revealed five major clusters. Ahigh96% diversity within Foc population indicated the presence of polymorphic loci in individuals of a given population evi-dent from results of Nei’s genetic diversity, Shannon information index, and polymorphism in-formation content values, apart from analysis of molecular variance (AMOVA). The current findings provide significant insights towards detection of Foc variants, and consequently the deployment of effective management practices to keep the possible epidemic development of disease under control along Malbhog banana growing belts of northeast India.