抄録
Wheat yield growth in Japan is limited compared to that in Germany, one of the European countries that produces wheat. Improving wheat productivity requires the diffusion of new varieties, because new varieties usually have higher yields than old ones. This study focuses on the differences in the diffusion of wheat varieties between Japan and Germany and comparatively analyzes the seed supply system and wheat handling unit in the two countries that affect the diffusion of varieties.
In Japan, farmers mainly grow varieties recommended by the local government. They often do not change varieties to prevent one variety from mixing with another. If varieties are mixed, the subsidy for wheat production decreases. In contrast, individual farmers in Germany choose their own varieties. Wheat is grouped by quality and then traded. They do not care about varietal mixtures because they do not affect farmers’ incomes. Farmers’ frequency changes vary; therefore, old varieties quickly change to new ones.
