Abstract
Several experiments were carried out on the relation between the sun light shortening and the damage caused by diseases of naked barley. The treatment was recognized to diminish the infection by the powdery mildew disease of naked barley, in spite of the favourable histological conditions for the fungus infection such as the imperfect silicification of leaves, the thinness of cuticular layers and insufficient development of cellulose. The fact seemed to be resulted by the consequence that the fungus growth was prohibited by the defect of nutrient substances in the host plant. The sun light shortening, in general, diminishes the living functions as carbon assimilation, causes lodging and results ultimately the remarkable decline of yield.
