Seventeen soybean (Glycine max L.)varieties representing 10 local, 5 Brazilian and 2 American ones were screened for their somatic embryogenic capacity using uniform in vitro culture methods. Auxin concentrations were optimized with five highest responsive varieties. The optimal concentration of 2,4-D for the varieties of Lianjiang, Zhechun 2, Perry and BRS 07 were found to be 2 mg/L, whereas that for Chief was 5 mg/L. Moreover, synergistic enhancing effects of two additives, copper sulfate and silver nitrate on embryogenesis were detected in separated experiments with Perry and BRS 07 when the media were supplemented with both at 5 mg/L.