Bakanae disease of rice has emerged as a major threat in the rice‐growingregions of Eastern and Northeastern India. Under field conditions, Fusarium species associated with bakanae disease of rice exhibit a significant degree of variability. Characterizing the pathogen and its isolates is crucial for understanding this variability. This study aimed to assess the genetic diversity and virulence patterns among 88 Fusarium isolates, the causal agents of rice bakanae disease, collected from various locations across Eastern and Northeastern regions of India. The isolates showed a significant variation in their morphology and virulence pattern. The genetic variability among isolates was assessed using 19 microsatellite markers, all of which were successfully amplified across the isolates. The observed genetic diversity was significant, as indicated by Shannon's information index for marker alleles. Using the marker allele differences among the isolates, pathogen population was subdivided into two groups. The analysis of molecular variance among two subpopulations demonstrated lower variance among population than within population. These findings suggest that the studied pathogen population comprises genetically distinct strains, ranging from highly virulent to moderately virulent. This study enhances our understanding of the diversity and distribution of Fusarium isolates, providing valuable insights for strategic breeding programs and effective disease management strategies.
Shivappa et al. (Wed,) studied this question.