Abstract
Some of the Japanese rice varieties are immune from a Philippine fungus strain of Pyricularia oryzae, in spite of their high susceptibility to most of the Japanese fungus strains. It was determined that this was controlled by two dominant genes; the one found in certain varieties among those belonging to the Shin 2, Aichi Asahi and Ishikari Shiroke groups, and the other in the Kanto 51 and To-to groups, the latter being identical to the gene Pi-k and the former being the gene allelic to the gene Pi-k. The latter was symbolized as Pi-ks. In addition to these, a few genes controlling high resistance when inoculated by spraying method were detected in Japanese varieties.
