Effects of Pinching on Growth and Yield of Different Soybean Cultivars

Abstract

Plants from six cultivars were pinched between the seventh and eighth nodes at stages V9–V10 or around V14 to examine the effect of pinching on growth and yield. Experiments were conducted under field conditions in 2016 and 2018, respectively. There was no significant difference in the degree of lodging between control and pinched plants. Pod number and seed yield values correlated significantly in these experiments; and, both were lower in the pinched plot than in the control, except for Kotoyutaka. Pinching increased branch pod number in Tamahomare, Fukuibuki and Kotoyutaka plants. However, this increase could not compensate for the decrease in the main-stem pod number of Tamahomare and Fukuibuki plants. In Kotoyutaka, the numbers, branch node and pod per node increased by pinching in low-order nodes; consequently, the pod number per plant was unaffected. These results suggest that the effect of pinching on soybean growth and yield components is cultivar-dependent. Cultivars for which pinching did not reduce yield were considered to have the ability to increase the node and pod per node numbers at low-order nodes.