1990 Volume 59 Issue 4 Pages 727-732
The purpose of this experiment was to clarify the significance of nodulation of soybeans (Glycine max (L.) Merr.) under the excess moisture condition. A pair of nodulating and non-nodulating lines, T202 and T201, were grown in an upland field converted from paddy. Flooding treatments were made in the furrows to the depth of 5 to 8 cm for 8 to 10 days at three different stages: the flower-bud differentiation, the flowering and the ripening. Nitrogen content in the leaf blade and dry matter production of both lines were decreased by the treatments in all stages, however those of T202 were not reduced so much as those of T201. At the flower-bud differentiation and the flowering stages, leaf nitrogen content and dry matter production of T202 recovered to the level of the control within 15 days after the end of the treatments, while those of T201 did not. Decrease in dry matter production induced by the treatments caused the decrease in seed yield, but seed yield of T202 was not reduced so much as that of T201. These differences in two lines were attributed to whether or not fixed nitrogen could be supplied by root nodules. As mentioned above T202, a nodulating line, could reduce excess moisture injury and could soon recover from it. Therefore, it can be proved that root nodules play an important role to reduce the excess moisture injury.
