1988 Volume 57 Issue 4 Pages 708-714
To demonstrate the effects of dwarf characters of the soybean on flowering and fruiting, which are closely related to the yield, cultivar Hyuga and its dwarf mutant Hyuga-dwarf line were used in this experiment. The results obtained are summarized as follows: 1. Anthesis of Hyuga-dwarf line concentrated almost in the beginning of flowering season similar to Hyuga, although the flowering period of Hyuga-dwarf line was shorter than that of Hyuga. 2. Hyuga-dwarf line exhibited a similar pattern of flowering and fruiting habits as Hyuga, i.e., percentages of flowering and fruiting were much higher on branches than on the main stem. In particular, this tendency was clearly observed in the branches elongated from the lower nodes of the main stem in Hyuga-dwarf line. 3. The total number of flowers of Hyuga-dwarf line was one-half of that of Hyuga. This was not due to the total node number, but to the number of flowers per node. 4. Since no difference in the number of pods per node between Hyuga-dwarf line and Hyuga was observed, it is indicated that the capacity of podding in a phytomer is limited. 5. Since the number of pods per unit stem weight showed the same tendency as the node number per unit stem weight, the high seed-stem weight ratio in Hyuga-dwarf line is considered attributable to a reduction in phytomer size. In conclusion, these results indicate that the number of flowers produced is limited by the amount of vegetative growth until the flower bud differentiation, and that the fruit percentage is limited by the vegetative growth increment after flowering and the number of pods per phytomer. In dwarf lines, the former seemed to be disadvantageous, whereas the latter seemed to be advantageous to crop production.
