Studies on the analysis of drought damage on paddy rice plants. : (I) the varietal difference of shoots.

[摘要] 1. Analysis of drought damage was made examing (a) damage by injurious insects and diseases and (b) drought damage from physiological and morphological relations. 2. As for physiological and morphological drought damage, varietal differences were observed by detecting the decreasing percentage of height of plant, number of stems and weight of panicles compared to control. In that result fairly high negative correlation was recognized between the decreasing percentage of number of stems and that of weight of panicles. When the percentage of crop yield decrease was compared, heavy panicle varieties of early on middle ripe type has shown less percentage than tillering late ripe one. 3. Among injurious insects Sesamia inferens WALKER keeps comparatively greater part. When varietal differences of insect damage were compared by injured panicle weight percentage for control/injured stem number percentage, it was recognized that the result came together with that of heretofore. 4. As for disease damage, that of the blast disease (Piricularia 0ryzae BRI. et CAV.) at spike-pedicel was found to keep almost all part. When compared by the method mentioned above the result of varietal differences came near that generally recognized. 5. Fairly high negative correlation seems to exist between outbreak of the blast disease at spike-pedicel by drought and degree of the development of the silicificated-short-cells in the epidermal tissue at spike-pedicel. 6. In test of drought resistance it is necessary to make analytical examination discriminating physiological and morphological resistance against that to diseases and injurious insects.

[学科分类] 农业科学（综合）