Morphological and Molecular Characterization of Fusarium Species Causing Crown and Root Rot in Winter Wheat

Abstract

Morphological and molecular characterization of Fusarium species associated with crown and root rot of winter wheat was undertaken to identify causal agents and assess their phylogenetic relationships. Diseased wheat plants exhibiting typical crown discoloration, root necrosis, and stunted growth were collected from field sites, and fungal isolates were obtained through tissue isolation on selective media. Morphological identification was based on colony characteristics, conidial morphology, and sporodochial structures observed under light microscopy. Molecular identification was performed using PCR amplification and sequencing of ITS rDNA and translation elongation factor 1-alpha (TEF-1α) gene regions. Phylogenetic analysis revealed that multiple Fusarium species complexes, including F. graminearum and F. culmorum, were predominantly associated with disease incidence, with clear genetic divergence among isolates indicating species-level variability. Combined morphological and molecular datasets provided improved resolution in distinguishing closely related taxa that were otherwise difficult to separate using morphology alone. Pathogenic variation among isolates suggested differential virulence potential contributing to disease severity in winter wheat fields. The study confirms the complex etiology of crown and root rot involving multiple Fusarium species and highlights the importance of integrative taxonomic approaches for accurate pathogen identification. These findings support the development of targeted disease management strategies and resistance breeding programs aimed at mitigating Fusarium-induced yield losses in wheat production systems.