Application of gibberellic acid to the surface of soybean seed (t Glycine max (L.) Merr.) and symbiotic nodulation, plant development, final grain and protein yield under short season conditions

Abstract

In short-season soybean production areas, low soil temperature is the major factor limiting soybean establishment, nodulation and nitrogen fixation. Gibberellic acid (GA) pretreatment of crop seeds can overcome low soil temperature inhibition of seed germination and seedling development. However, previous studies have found that the application of GAs decreased legume nodulation and nitrogen fixation under optimal growth conditions. A field experiment was conducted under short season conditions in eastern Canada to determine whether the application of GA3 to soybean seed could accelerate germination, and increase plant nodulation and nitrogen fixation. The results indicated that GA3 application accelerated seedling emergence but decreased plant nodulation and nitrogen accumulation at early plant growth stages. However, these initial negative effects were overcome as the plants developed. Gibberellic acid applied to soybean seed at the time of planting did not influence final grain and protein yield.