Abstract
1) The toughness and the percentages of silica and nitrogen of the leaf blades of rice varieties were measured to find the relation between these properties and the varietal resistance of rice to the blast disease.
2) Rice varieties used for this purpose were Ban-Sinriki, Kamezi, Sensyo, Aikoku, Asahi, Ginbozu, Sinzyu-1, and Kamairazu.
3) These plants were water cultured during summer season under glass roof using modified KASUGAI's solution in which three times the normal quantity of nitrogen component was given.
4) Resistance to rice blast of these varieties was tested either by inoculating Piricularia oryzae to the plants, or examining the plants affected naturally by the blast fungus.
5) Comparing the results thus obtained with each other, it is found that the varietal resistance of rice to the blast disease is not correlated to the variation of these physical and chemical properties of rice varieties.
