Abstract
The gametocidal inhibitor gene (Igc1) and β-amylase isozymes of Asian common wheat cultivars were ana-lyzed to investigate a possible transmission route of common wheat to China and the eastern Asia. Frequency of lgc1 was clearly different between areas, being frequent in East China, Sichuan and Southwest Japan, and sporadic in Northeast China, Inner Mongolia, Xinjiang, Tibet and the westwards. In the bordering regions, both carriers and non-carriers of lgc1 were observed. Common wheat cultivars in east Asia can be, therefore, clearly characterized by this gene. A unique zymogram type J of β-amylase distributed only in Xinjiang, Northwest China, East China and Southwest Japan but not in the other regions. These specific distributions of adaptively neutral characters suggested the transmission route of common wheat to East China and Japan: It was introduced from Xinjiang to North-west China through so-called ‘silk-road'. During transmission, the population size must have once decreased, and plants with less genetic variation became founders of common wheat in East China, Sichuan and Southwest Japan. On the other hands, the cultivars in Northeast China, Inner Mongolia and Tibet were introduced through different ways.
