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ABSTRACT
An experiment was conducted in the field of SAU (Sher-e-Bangla
Agricultural University) farm, Dhaka to screen out the resistant varieties of
rice against sheath blight (Rhizoctonia solanikuhn) during Aus season in
2007. Seven rice (Aus) varieties viz. BR3, BR14, BR16, BR21, BR26 and
BRRI dhan 27 were used as treatments. The screening of the varieties were
done based on different parameters like disease incidence, disease severity,
yield and yield contributing characters. The highest lesion size was recorded
in the variety BR16 (4.02 cm) and lowest lesion size (3.50 cm) was in BRRI
dhan 27 at maturity stage. The value of the relative lesion height (%RLH)
was large in the susceptible variety and small in the moderately susceptible
variety. Among the varieties, BR3, BR14, BR21, BR24, BR16 and BR26
were graded as susceptible and BRRI dhan 27 was graded as moderately
susceptible to sheath blight. The disease was more severe in advanced
growth stages of the plants. The highest grain yield per hectare (3.00 t/ha)
was recorded in the variety BRRI dhan 27 and the lowest grain yield (1.14
t/ha) was recorded in the variety BR24. The highest weight of thousand
grains (32.73 gm) was recorded in the variety BRRI dhan 27 and the lowest
weight of thousand grains (29.43 gm) was recorded in the variety BR3.
BRRI dhan 27 performed better in respect of all the parameters considered
against sheath blight of rice.
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