Possible Transmission Route for Common Wheat to the Far East in Asia

High molecular weight (HMW) glutenin alleles, such as Glu‐D1 , have an important effect on the quality of Japanese noodles (udon). The Glu‐D1f allele is of particular significance to common wheat ( Triticum aestivum L.). The frequency of the Glu‐D1f allele differs among geographical areas, and it has been identified in wheat from northern and southern Japan, from Xinjiang, Nanjing, Zhejiang, and Beijing in China, the Korean Peninsula, and Afghanistan. However, a particularly high frequency of the Glu‐D1f allele has been found in wheat from southern Japan. On the basis of the distribution of an adaptively neutral character, two specific routes of transmission of common wheat to the Far East have been suggested. In the first scenario, common wheat was introduced from Afghanistan, transported to Xinjiang in northwest China, then to Shaanxi, Nanjing, and Zhejiang in southeast China, and finally to southern Japan along the so‐called Silk Road. In the second scenario, common wheat was introduced from Afghanistan, transported to Xinjiang in northwest China, then to Shaanxi and Beijing in northeast China, then to the Korean Peninsula, and finally to southern Japan. In a previous study, only the Chinese Route was revealed. Through the course of its transmission and its adaptation to diverse local environments, Japanese common wheat has developed a unique composition of glutenin Glu‐D1 alleles, including Glu‐D1f