Total of 235 single spores were isolated from the infected rice plants and about 85% (200) single spores were characterized, of which 50, 100 and 85 monoconidial spores were isolated from the north; center and southern regions, respectively. 
From 200 isolates were classified into 92 pathotypes, within 92 pathotypes were classified into 12 races types A, B, C, D, E, F, G, H, I, J, K and N. The predominant race types A, B, C, D and E were observed mostly in rainfed ecosystem of center and southern regions. The highest virulent frequency was observed in 5 monogenic lines IRBLa-A (Pia), IRBL19-A (Pi19), IRBLks-S (Pik-s), IRBLzt-T (Piz-t) and IRBLt-K59 (Pit), ranged from  83, 77, 74, 72 and 67%, respectively. In other hand, the lowest frequency was observed in 6 monogenic lines IRBLkh-K3 (Pik-h), IRBLta2-Re (Pita2), IRBLta2-Pi (Pita2), IRBL9-W (Pi9), IRBLsh-S (Pish) and IRBLz-Fu (Piz), ranged from 12, 11, 9, 2, 2 and 0%, respectively. Monogenic line IRBLz-Fu which is harboring resistant gene Piz shows universal resistance to all blast isolates. In addition, monogenic line IRBLsh-S which is harboring resistant gene Pish shows resistance to most of blast isolates collected within the country, except the isolates collected from the upland ecosystem in the southern region. 

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