S. NAKAO and T. KAWASE
Faculty of Agriculture, University of Osaka Prefecture, Sakai, Japan and Faculty of Agriculture, Kyoto University, Kyoto, Japan
The wheat varieties of standard productivity recommended by the government to the farmers are registered by the Norin numbers. Norin is the abbreviation of the Department of Agriculture and Forestry. From 1926 up to the present, 90 Norin varieties have already been established. Through the studies on various hybrid progenies it became clear that high productivity together with early maturing habits and disedase resistance can be secured only by crossing of selected parents. Therefore, the parents of the Norin varieties are few in number. For example, Norin winter wheats for the snowy parts of Japan have been raised as follows:
