Genetic Structure and Aggressiveness of Fusarium culmorum Isolates Collected from Crown Rot of Barley

Abstract

Genetic structure and aggressiveness of Fusarium culmorum isolates collected from crown rot of barley were investigated to understand population diversity and pathogenic variability associated with disease severity. Field surveys were conducted in barley-growing regions exhibiting crown rot symptoms, including basal stem browning, root decay, reduced tillering, and plant stunting. Fungal isolates were obtained from infected tissues and characterized using morphological features such as colony pigmentation, growth rate, and conidial morphology. Molecular analysis was performed using PCR-based markers and sequencing of ITS and related genomic regions to assess genetic diversity and phylogenetic relationships. Results revealed substantial genetic variation among isolates, with distinct clustering patterns indicating the presence of multiple genetic lineages within barley-associated populations. Pathogenicity assays conducted on barley seedlings demonstrated significant differences in aggressiveness among isolates, with highly virulent strains causing severe crown rot symptoms and marked reductions in plant biomass. Correlation analysis suggested a positive association between specific genetic groups and higher virulence levels. Environmental adaptation and host–pathogen interactions were inferred to contribute to the observed variability in aggressiveness. The study highlights the importance of integrating molecular and pathogenicity data to understand population dynamics of F. culmorum. These findings provide valuable insights for breeding disease-resistant barley cultivars and developing targeted management strategies to mitigate crown rot severity in cereal production systems.