Screening of Rice Genotypes for IA-82 Race of Blast

One of the most important diseases of rice in Iran is blast which causes yield reduction in susceptible rice cultivars. In this study, 60 rice genotypes with two cultivars of Nemat and Binam, resistant and susceptible local controls, respectively, were evaluated for resistance to leaf blast in greenhouse in 2011. Evaluation of infection type, number of sporulated lesions, percentage of infected leaf area and lesion size traits for IA-82 isolate showed that IRBL5-M, IRBLZ5-CA, B40, CT18235-3-9-1-2-3-4 and CT18617-6-2-2-3-1 genotypes were susceptible and infection type more than 3 and lesions produced were sporulated. IRBL12-M, IRBLZT-T, CT18232-5-9-1-2-6-3, CT18615-1-5-1-2-1 and IR33225-453-1-1 genotypes to IA-82 isolate were resistant moderately and also 48 genotypes were resistant to IA-82 isolate. Rice genotypes were grouped based on the studied traits for IA-82 isolate. Rice genotypes with similarity coefficient of 0.85 can be divided into 2 groups. The first group consisted of 33 genotypes including Nemat (local resistant cultivar). Genotypes of this group showed resistant reaction for infection type and no sporulated lesions and the percentage of infected leaf area and lesions size showed lower values.