抄録
Development of varieties with high resistance to blast disease had been an urgent need for rice production in the 1960s and 1970s, since blast epidemics prevailed on excellent varieties with resistance derived from some Chinese, U.S.A. and Philippine varieties. Our breeding project introduced high resistance from typical Indica varieties into the genetic backgrounds of Japanese varieties by backcross breeding, and developed Toride 1, Toride 2 and BL1 to BL7. Toride 1 and Toride 2 inherited Piz-t gene for resistance from Indian varieties, and BL1 to BL 7 inherited Pib gene from Indonesian and Malaysian varieties. Although Piz-t and Pib distributed widely among Indica varieties of South Asian countries showed resistance to a number of blast races in Japan, they were vulnerable to naturally-occurring virulent mutants. This paper reviews how Piz-t and Pib were introduced, identified, and utilized in the breeding and genetic researches conducted by the author and co-workers since 1960.
