Relation between the Rooting Ability from Flag Leaf Node and the Cool Tolerance at the Booting Stage in Rice

[摘要] Studies were conducted to clarify the relation between the rooting ability from flag leaf node and the cool tolerance at the booting stage in rice. Panicles with the flag leaf nodes were taken from plants just after the heading and kept in water, cutting out the stems at 3 to 5 cm below the flag leaf nodes. Days from the start of the treatment to the rooting were evaluated as the rooting ability. In the 15°C treatment, rooting was not found. In the 25°C and 30°C treatment, the rooting ability of varieties from the flag leaf nodes was closely correlated with the cool tolerance. Rooting from the flag leaf nodes was rarely found when panicles were taken after heading. On the contrary, rooting ability was higher when panicles were taken before heading than just after heading. Although rooting ability became lower when panicles were taken after irrigation with cool water before heading, rooting ability of the varieties with the cool tolerance was higher than that of the varieties with cool sensitivity. The rooting ability of F2, F3 and F4 progenies between two varieties of high and low tolerance for cool temperature at the booting stage were tested. Relation between the rooting ability and cool tolerance was not clear, probably because the fixation degree of these progenies was not enough. It is necessary to investigate this relation using the more advanced progenies.

[学科分类] 农业科学（综合）

[关键词] Booting stage;イネ;Cool tolerance;耐冷性;Flag leaf node;止葉節;Rice;発根速度;Rooting ability;品種間差;Varietal difference.;穂ばらみ期.