Studies on Blooming and Fruiting in Soybean Plants, especially on the Relationship between Blooming and Fruiting on Each : Node in soybean plants and weather conditions and production practices.

Abstract

The variety, Norin No. 4, were seeded on 15th May and 30th June in 1958 and 1959 with two stands, light and heavy. The blooming and fruiting in each node were observed. The results obtained are as follows: 1) The weight of leaves and stems and the number of pods were larger on the early seeding plot than the late one, on the plot of light density than the heavy stand and in the test in 1958 than 1959 especially on the early seeding plot. The percentages of fruiting were not constant with plots. 2) There were a fundamental type of blooming and fruiting in each node of both of the main stem and branches of the plant, the largest number of flowers and pods were observed on the top node and the 6th to 8th node from the top, and the fruiting percentage and mean weight of a seed were high on the node of the second to 5th node. 3) However, there were some differences with production practices, the number of flowers and pods in the branches were changeable in each node but on the main stem they were favorably constant especially on the second to 5th node. Higher yields were obtained when the nodes with many flowers and pods were shown on relatively lower position. The more differences were shown between the most efficient node of flowering and podding the lower fruit-setting percentage were observed. 4) Such differences of flowering and fruiting came mainly from the differences of the duration of sunshine, the light intensity on the lower leaves and the growth of leaves and stems. Consequently, the number of flowers depended upon the amounts of the reserves of assimilates untill the period of the differentiation of flower buds and the pods number depended upon the amounts of the assimilates during 30 days after the blooming stage. 5) It was clarified that the important period and leaf position to decide the number of flowers and pods were different and there were some changeable nodes in the number of flowers and pods with production practices. The data shown might be very important to promote the soybean yields.