Cultural, morphological and molecular characterization of Bipolaris oryzae causing brown leaf spot of rice in Northern Karnataka

Abstract

Rice brown leaf spot disease is one of the most destructive disease causing enormous yield losses to rice in different rice growing regions of the world. The present study aims to identify and characterize the rice brown spot pathogen Bipolaris oryzae from different rice growing regions of northern Karnataka. Among the different media’s tested, potato dextrose agar showed maximum radial growth (89.33 mm) in all the isolates followed by host extract dextrose agar (87.25 mm). Different isolates showed different colony characters, colony diameter, margin, mycelia growth, spore germination and sporulation. Molecular characterization of all the ten isolates was done with two ITS primers. In phylogenetic analysis, the brown spot isolates were grouped into two major clusters. The molecular studies confirmed them to be as Bipolaris oryzae. Our study showed high degree of genetic variation among the isolates collected from different locations.