Detection of blast
resistance gene(s) in some rice genotypes using molecular markers and pathogenicity
assessment
Rownok Zubair-Al-Mahmud, Haque Mohammad Mahbubul, Bir Md. Shahidul Haque, Hossain
Muhammed Ali and Ali Md. Arshad
Res. J. Biotech.; Vol. 21(2); 54-61;
doi: https://doi.org/10.25303/212rjbt054061; (2026)
Abstract
Blast is one of the most devastating rice diseases in Bangladesh and the pathogen
of blast is Magnaporthe oryzae. In this work, employing four molecular markers,
namely RM276, RM403, RM 302 and RM 155, an effort was made to identify seventy-nine
rice genotypes for four important blast-resistant genes, Pi9, Pita, Pish and Pita-2.
Screening was done by the Plant Pathology Division, BINA and the Department of Plant
Pathology, BAU. Findings indicated that just three genotypes contained the rare
Pita-2 gene, while 54 genotypes carried the Pi9 gene, 44 Pita gene, 23 Pish gene
and so on. Pi9 was the most common resistance gene, with genetic frequencies ranging
from 6.12% to 77.5%. One genotype was resistant, sixteen were somewhat susceptible,
eleven were somewhat resistant, sixteen were susceptible and three were highly susceptible
according to phenotypic screening. One genotype was resistant, sixteen were relatively
susceptible, eleven were moderately resistant, sixteen were susceptible and three
were highly susceptible, according to phenotypic screening.
When compared to genotypes with a single gene, the advanced line BN-P-102, which
possessed all four resistance genes, demonstrated increased resistance. The blast
disease propagated quickly, according to the area under the disease progress curve
(AUDPC) approach, with 7.67% of plants afflicting 7 days after inoculation (DAI)
and 11.92% by 21 DAI. According to the research, BN-P-102 and Sete Pajam-2 show
promise as blast-resistant rice cultivars. Furthermore, the results of the AUDPC
highlight how crucial early disease control is in the field.
