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Specific Glu-D1ƒ Allele Frequency of Japanese Common Wheat Compared with Distribution of Glu-1 Alleles in Chinese Wheat

¹National Agricultural Research Center for Tohoku Region, Fukushima Campus, Fukushima 960-2156, Japan. ²Corresponding author. Phone: 81-24-593-6178. Fax: 81-24-593-2155. E-mail: hiro@affrc.go.jp. ³Tokyo University of Agriculture, Tokyo 156-8502, Japan.

The quality of wheat (Triticum aestivum L.) grain favored in breadmaking is strongly affected by components of seed storage protein, particularly high molecular weight glutenin subunits (HMW-GS). The HMW-GS 2.2 controlled by the Glu-D1ƒ allele is frequently found in Japanese cultivars and landraces. In the investigation into the factors affecting the distribution of the allele, the available data on HMW-GS of common wheats from Japan were analyzed and compared with the data for intensity of winter habit and wheat flour hardness. We show that the main factors affecting the Glu-D1ƒ allele frequency in Japanese wheat were the intensity of natural selection for winter habit and artificial selection for flour hardness. According to a study of the worldwide distribution of Glu-1 alleles, the Glu-D1ƒ allele is rare. However, Glu-D1ƒ allele was the most common Japanese wheat seed storage protein allele. It is well known that Chinese wheat contributed to Japanese landraces, and Japanese landraces contributed to modern cultivars from Japan. However, common Japanese and Chinese wheats differ in the frequencies of Glu-D1ƒ allele. These results may be explained either by the founder effect or by a selective bottleneck in Japanese common wheat genetic resources.