Abstract:
Abstract
Experiments were conducted at Mycology Laboratory, Department of Plant
Pathology, Sher-e-Bangla Agricultural University, Dhaka from July 2018 to June
2021 to study morphological and molecular characterization of rice blast pathogen
Magnaporthe oryzae (Mo) that has become a major factor limiting rice yield
throughout the world. Initially survey was done in twenty (20) rice growing
districts of Bangladesh and rice blast samples (infected leaf, neck and node) were
collected. Five different media including Water Agar (WA), Potato Dextrose Agar
(PDA), Potato Sucrose Agar (PSA), Rice flour Yeast Agar (RN A) and Oat Meal
Agar (OMA) were used to compare growth of Mo. Colony characters like growth
character, color, surface structure and shape of 100 Mo isolates were recorded in
OMA. Isolates were pathogenic to US2 and BRRI Dhan 28. In molecular
identification (ITS rDNA gene) PCR using primer pairs ITS I/ITS4 yielded
approximately 600 bp band of amplification product for representative isolates of
Magnaporthe. Among the five different growth media highest mycelia growth
rate was observed in OMA and lowest in WA. Colony color of all the isolates was
whitish, greenish, brownish, white gray, light brown etc. Six (6) resistant
germplasms were screened against Mo and would be useful in future rice blast
resistant variety development program.
Keywords: variation, Magnaporthe oryzae oryzae, screening, rice genotype, resistant, blast
