Received: 22 April 2019; Accepted: 19 October 2019

Abstract

Brown spot disease (Bipolaris oryzae) has been associated with two major epidemics in India and one of the strongest yield reducers among rice diseases in recent years. The disease especially occurs in environment where water supply is scarce combined with nutritional imbalance particularly lack of nitrogen and hence often referred to as ‘poor man’s disease’. In the present study, six isolates of B. oryzae were used for extraction of toxin by solvent extraction procedure. Toxin profile of six isolates of B. oryzae on Thin-layer chromatography (TLC) plate showed a total of eight bands; five bands at Rf 0.93, 0.85, 0.77, 0.61 and 0.49 were distinct and all isolates produced a common dark band at Rf 0.61 in iodine chamber at 254 nm. The quantitative analysis of toxin produced by different isolates was carried out by Highperformance liquid chromatography (HPLC) analysis. Six isolates of B. oryzae showed variation in their peak values at different retention time. In all isolates unique peak with retention time at 4.3 min was observed. This compound which was observed in all the isolates can further be characterized for its property of toxin by using distinct standards.