ASSESSMENT OF WHEAT BLAST INTENSITY IN SOUTH WEST OF BANGLADESH AND CHARACTERIZATION OF MAGNAPORTHE ORYZAE TRITICUM ON DIFFERENT CULTURE MEDIA

Abstract

This study was carried out to determine the incidence and severity of wheat blast, isolation and pathogenicity of Magnaporthe oryzae triticum (MoT) isolates and evaluation on different culture media for their growth and cultural characteristics. Wheat blast were assessed in 30 farmers' fields in two districts during the Rabi cropping season in February to March 2019, in major wheat growing areas viz. Meherpur, Mujibnagar and Chuadanga. The results of the assessment revealed that the wheat blast incidence and severity varied from low to high depending on the survey sites and crop varieties. The highest incidence and severity, 100% for all areas were recorded in BARI Gom-24 (Prodip) followed by BARI Gom 26 and BARI Gom 28 in entire three districts. A total of 15 MoT isolates were identified and characterized based on their growth parameters. Among them, ten isolates such as ME MoT13, ME MoT14, ME MoT15, ME MoT16, MU MoT13, MU MoT14, MU MoT15, MU MoT16, CH MoT11 and CH MoT12 were evaluated on the eleven culture media such as Oat meal agar, Corn meal agar, Prune agar, Yeast extract agar, V5 agar, Wheat straw agar, Potato dextrose agar, Potato carrot agar, Wheat seed extract agar, Wheat flour agar and Potato sucrose agar. MoT isolates showed comparatively higher mean radial mycelial growth on OMA (51mm) followed by Yeast extract agar (48.33mm) and Wheat flour agar (44.57mm) at 4 DAI. Minimum mean radial mycelial growth was recorded on CMA (16.2mm). The radial mean mycelial growth was also sufficient on PDA, PSA and Wheat straw agar.

Key words: Wheat blast, incidence, severity, culture media, Magnaporthe oryzae triticum