Abstract
Twenty four Japanese varieties with known level of field resistance in Japan were tested with three Philippine fungus strains and two Japanese ones in a greenhouse experiThe three Philippine strains were chosen for their virulence to the tested ment. varieties out of 80 isolates. The three strains were confirmed to have differential virulence to some selected resistance types in the Philippines. Against two Japanese strains, the resistance manifested by four upland varieties was very high in accordance with previously reported data. Although the infection was too severe to differentiate clearly the level of field resistance among ordinary lowland varieties, several varieties including Yamabiko and Kogane Nishiki were less severely infected than Norin 29 and Koshihikari in accordance with a general tendency in Japan. Against the Philippine strains, the level of the infection was, as a whole, lower than those caused by Japanese ones. However, the highly susceptible reaction of Norin 6 and Aichi Asahi indicated that the infection was severe enough to differentiate the fleld resistance among the entry
