Effect of terminal bud clipping on growth and yield of soybean cultivars in the Pacific Northwest

Abstract

AbstractSoybean [Glycine max (L.) Merr.] is one of the four major staple crops and the world's most important vegetable protein source. Very little information is available on the performance, yield, and cultivars of soybean when choosing a cultivar to grow in Pacific Northwest (PNW). Of the oilseed crops, soybean appears to have the best potential to be grown at a profit (high yields) in PNW when considering the high input costs for irrigated crops. The present study was conducted to determine if terminal bud clipping would increase yields of soybean cultivars under irrigated conditions in 2‐year field experiments. Five soybean cultivars were planted in four‐row plots with rows 0.13 m apart. Plots were replicated four times with two treatments (early clipping and late clipping) and control in a randomized complete block design. Data regarding yield and growth traits were recorded using standard procedure. Soybean yield was significantly influenced by the year of production and terminal bud clipping, whereas cultivars showed no effect. Early and late clipping resulted in a 15% and 18% increase in yields in 2018, whereas late clipping resulted in a 16% yield increase in 2019 compared to control. Terminal bud clipping resulted in shorter plants and reduced lowest pod height, lodging, and maturity compared with the control. Lodging and maturity decreased with late‐maturing cultivars. Finally, results suggest that terminal bud clipping increases soybean yields. Early maturing cultivars (maturity group 0.4) are unsuitable for PNW due to the lowest pod height.