Seed production of wild soybean (Glycine soja Sieb. et Zucc.) under favorable, ruderal, and natural growing conditions.

Field trials were conducted in Japan under different growing conditions to better understand seed production of wild soybean (Glycine soja Seib. et Zucc.). The objectives of these trials were to evaluate yield and yield components of wild soybean: (1) across 11 diverse populations grown under favorable conditions to assess seed production potential, (2) under different planting densities (112, 208, 416, and 832 plants/m2) to assess intra-specific competition, and (3) across growing conditions (favorable, ruderal, and natural) to assess the impacts of environmental stress and inter-specific competition. Significant differences in yield and seed number observed among the evaluated wild soybean populations were predominantly due to environmental effects and genetic by environmental interaction. Seed production was impacted by both intra- and inter-specific competition. Wild soybean grown without plant competition had 51-fold and 247-fold higher yield compared to when grown in ruderal and natural environments, respectively. Under favorable growing conditions, wild soybean had substantial yield potential due to the ability to produce a high number of seeds. In nature, yield potential is severely limited because of plant competition and other environmental stressors. The results of this research are useful to inform environmental risk assessment when considering the potential impact of soybean biotechnology traits that increase or protect yield. If such traits were to be inadvertently transferred from imported soybean into wild soybean, this research indicates that the effects would likely have little overall impact on wild soybean seed production.