With the objective of identifying the physiological races of Pyricularia grisea which occur in Minas Gerais, samples of rice leaves with blast lesions were collected from 15 locations. Three single spore isolates from each one of the two lesions obtained from 23 samples were analyzed. Races were identified according to the reaction pattern on eight standard international differentials utilizing the visual rating scale of 0 to 9. Races IA-1, IA-9, IA-10, IA-13, IA- 65, IA-73, IB-1, IB-9 IB-15, IB-1, IB-64, IC-9, IC-14, IC-16 were identified. The predominant race IA-9 was identified in 41.18% of the isolates , followed by IA-1 in 18.37% and IB-9 in 16.92%. Different physiological races of P. grisea were identified from isolates obtanied from a single lesion indicating high variability of the fungus.
Oryza sativa; Magnaporthe grisea; genetic resistance
