Blast of rice, caused by Pyricularia grisea, is one of the most important diseases of rice in
Nepal. It has been causing significant yield loss in all rice growing areas. A field screening
experiment was conducted to identify resistance in rice to the disease during 2011 and 2012
wet season at Regional Agricultural Research Station, Tarahara. A total of 134 (OBN -70,
RA VTRL-26, RA VTN-22 and Quality-16) rice genotypes were evaluated for resistance in
both the years. atural spread of the pathogen in the test lines was allowed from border lines I
inoculums rows planted around the nursery with mixture of susceptible varieties (i.e. Mansuli
and Sankharika). Conducive environment for blast development was created by planting four
rows of Sesbania eculeata around the experimental plot 35 days prior to seeding of test
genotypes. Scoring was done on 22 days after seeding and continued for three scorings at 7
days interval using 0-9 scale developed by IRRI. Area under disease progress curve (AUDPC)
varied significantly among the tested rice genotypes in both years. Disease severity varied 0 to
77.77%. Out of 134 entries, 58 entries were resistant to the disease during 2011 and 63 in
2012. Among them, IR09Fl12, IR09Fl20, IR09Fl27, IR09F158, IR09Fl66, IR09Fl74,
IR09F 178, TR09F226, IR09F229, IR09F236, IR09F238, R09F253, IR09F293, IR-64-Sub-1,
IRRI-119, lET 14846, WAS 202-B-B-13 , IR 75299-94-1-2-2, IR 73007-131-1-2-2, 1R 70215-
70-CPA3-4-1-3, IR 80411-B-28-4, IR 79913-B-176-B-4, IR 78937-B-20-B-B-4, BR 4363-3-
8-1-2-4(BR-32), Basundhara, Tarahara-1, Hardinath-2, Sura vi and Mahima were free from
blast in both the years. The number of moderately resistant (3 -4), moderately susceptible (5 -6)
and highly susceptible (7-9) genotypes was 43, 9 and 2 in 2011 and 54, 3 and 1 in 2012,
respectively. Disease severity increased in second and third scorings in all entries except the
resistant ones. IR09Fll0, NR 1887-8-1-1-2 and Kanchhi masuli were highly susceptible to
blast with the highest disease score (7) which were completely knocked down in the final
scoring.

Blast of rice, caused by Pyricularia grisea, is one of the most important diseases of rice in
Nepal. It has been causing significant yield loss in all rice growing areas. A field screening
experiment was conducted to identify resistance in rice to the disease during 2011 and 2012
wet season at Regional Agricultural Research Station, Tarahara. A total of 134 (OBN -70,
RA VTRL-26, RA VTN-22 and Quality-16) rice genotypes were evaluated for resistance in
both the years. atural spread of the pathogen in the test lines was allowed from border lines I
inoculums rows planted around the nursery with mixture of susceptible varieties (i.e. Mansuli
and Sankharika). Conducive environment for blast development was created by planting four
rows of Sesbania eculeata around the experimental plot 35 days prior to seeding of test
genotypes. Scoring was done on 22 days after seeding and continued for three scorings at 7
days interval using 0-9 scale developed by IRRI. Area under disease progress curve (AUDPC)
varied significantly among the tested rice genotypes in both years. Disease severity varied 0 to
77.77%. Out of 134 entries, 58 entries were resistant to the disease during 2011 and 63 in
2012. Among them, IR09Fl12, IR09Fl20, IR09Fl27, IR09F158, IR09Fl66, IR09Fl74,
IR09F 178, TR09F226, IR09F229, IR09F236, IR09F238, R09F253, IR09F293, IR-64-Sub-1,
IRRI-119, lET 14846, WAS 202-B-B-13 , IR 75299-94-1-2-2, IR 73007-131-1-2-2, 1R 70215-
70-CPA3-4-1-3, IR 80411-B-28-4, IR 79913-B-176-B-4, IR 78937-B-20-B-B-4, BR 4363-3-
8-1-2-4(BR-32), Basundhara, Tarahara-1, Hardinath-2, Sura vi and Mahima were free from
blast in both the years. The number of moderately resistant (3 -4), moderately susceptible (5 -6)
and highly susceptible (7-9) genotypes was 43, 9 and 2 in 2011 and 54, 3 and 1 in 2012,
respectively. Disease severity increased in second and third scorings in all entries except the
resistant ones. IR09Fll0, NR 1887-8-1-1-2 and Kanchhi masuli were highly susceptible to
blast with the highest disease score (7) which were completely knocked down in the final
scoring.