Effect of flower or pod removal on the performance of soya beans (Glycine max. L.)

Summary All flowers were removed daily on soya-bean plants (cv. Hampton) for 1, 2, or 3 weeks and all pods developed on the plant were removed after 1, 2 or 3 weeks of pod development, in two field trials, in order to evaluate the effects of removing flowers or pods on the growth, development and yield of the cultivar. Removal of flowers or pods led to less dry-matter accumulation, longer leaf area duration and delayed maturity of the plants and these became more pronounced with the severity of the removal. Number of mature pods per plant, number of seeds per plant, pod yield per plant and seed yield both per plant and per hectare, were significantly reduced when flowers were removed for 1 week or pods removed after 2 or 3 weeks of development in the early season crop. Yield was reduced by 27%, 35% and 40% respectively both per plant and per hectare. In the late season crop, removing flowers for 3 weeks or removing pods after 3 weeks of development led to significant reduction in number of mature pods per plant, number of seeds per plant, number of seeds per pod, pod yield per plant and seed yield both per plant and per hectare. The magnitudes of yield reduction were 40% and 49% respectively. The ability of the variety of soya bean used in this study to prevent significant reduction in seed yield by compensatory development, following flower or pod removal, depends on the severity of the removal vis-d-vis the stage of development of the plant and its vigour.