Foliar Blast Disease
The foliar blast screening is done in a plant house under natural infection as described by IRRI (Anon, 2014). Planting method for the screening system consists of testing row, border row and inoculum bed. Testing rows of ~30cm in length (1 row per test line) is ~5cm apart is sown in between two border rows. Border rows serve as spreader rows by continuously supplying inoculums to test lines. Inoculum bed which consist a mixture of several susceptible local varieties is planted continuously at one week interval. This is to ensure presence of inoculum consisting diverse pathotypes of Pyricularia oryzae airbone spores including those in farmer’s field. Seedlings were watered frequently by sprinkler at every three hours interval throughout the day. Urea fertilizer is applied at 2 weeks after sowing at the rate of 140kg N/ha. Disease reaction was assessed based on symptoms at 21 and 28 days after sowing (DAS) using a 0-9 scale as described by 5th edition of the Standard Evaluation System for Rice (SES, IRRI) (2013).
Legend:
Highly resistant
Resistant
Moderately resistant
Moderately susceptible
Susceptible
Very susceptible