This paper examines the history of Japanese genetics in the 1920s to 1950s as seen through the work of Hitoshi Kihara, a prominent wheat geneticist as well as a leader in the development of the discipline in Japan. As Kihara's career illustrates, Japanese genetics developed quickly in the early twentieth century through interactions with biologists outside Japan. The interactions, however, ceased due to the war in the late 1930s, and Japanese geneticists were mostly isolated from outside information until the late (...) 1940s. During the isolation in wartime and under the postwar U.S. Occupation, Kihara adapted to political changes. During wartime, he developed a research institute focusing on applied biology of various crops, which conformed to the national need to address food scarcity. After the war, he led the campaign for the establishment of a national institute of genetics and negotiated with American Occupation officers. The Americans viewed this Japanese effort with suspicion because of the rising popularity of the controversial theory of the Russian agronomist, Trofim Lysenko, in Japan. The institute was approved in 1949 partly because Kihara was able to bridge the gap between the American and Japanese sides. With Kihara's flexible and generous leadership, Japanese genetics steadily developed, survived the wartime, and recovered quickly in the postwar period. The article discusses Kihara's interest in cytoplasmic inheritance and his synthetic approach to genetics in this political context, and draws attention to the relation between Kihara's genetics and agricultural practice in Japan. (shrink)