Increased Pod Set of Determinate Cultivars of Soybean, Glycine max, with 6-Benzylaminopurine

Terminal racemes on determinate soybean, Glycine max (L.) Merr., cultivars Bragg and Lee were treated with three concentrations of the cytokinin 6-benzylaminopurine (BAP) to reduce pod abscission. A 1-mM BAP treatment significantly reduced pod abscission and increased the total number of pods and seeds per raceme. The effect of BAP on reducing pod abscission was apparent within 6-10 d of initial treatment. BAP caused a more than a sixfold increase in seed set for cv Bragg and almost a fourfold increase for cv Lee racemes. The greater seed numbers resulted from increased pod set. However, BAP had no effect on the distribution of one- to four-seeded pods on racemes or the percent aborted seeds within harvestable pods. A significant change in location of set pods on the rachis axis was observed for the BAP treatment