method (Arase et al., 1990). The spore concentration of M. oryzae
was adjusted to 210
5
spores/ml using a hemocytometer. Rice
cv. Koshihikari, which has non-blast-resistant Pi-genes and is thus
susceptible to isolate Naga 69-150, was used in this study. Seedlings
were planted in a seedling case with commercial soil (Sun Soil
S, Nagata KK, Japan) and then grown in a greenhouse, as reported
previously (Arase et al., 1990)