Conditions required for simple evaluation of field resistance to panicle blast in rice cultivars using spray-inoculated cut panicles were studied in 49 rice cultivars and strains with different levels of field resistance to blast. To obtain cut panicles, tillers consisting of a panicle, the boot leaf and one culm node were cut from field or pot grown rice plants at the full heading stage. Cut panicles were placed in plastic cases containing water and inoculated by spraying with a spore suspension of Pyricularia grisea (2×105 conidia/ml). The percentages of spikelets diseased with panicle blast were assessed 14-16 days after inoculation. Statistically significant positive correlations were found between the cut panicle test and field trial for the percentage of diseased spikelets. High positive correlations were also obtained when cut panicles were kept at 25-30°C after inoculation. Sampling sizes required to obtain 10 and 15 sampling errors (P=0.05) were 19 and 10 panicles from pot grown plants and those from paddy plants were 15 and 8 panicles, respectively.
