Optimization of soybean (Glycine Max L.) regeneration for korean cultivars

Tissue culture could provide key insights into the development of transgenic plants, production of good cultivars and secondary metabolites, conservation of endangered plants, and safeguarding of germplasms. In this study, the effects of shoot induction media, explants, cultivars, and phytohormone concentrations on the regeneration efficiency of Korean soybean cultivars were evaluated. Restricted dormancy and poor germination may affect regeneration, depending on the type of germination medium or initiation of phytohormone treatment. Therefore, we analyzed the effects of different germination media containing plant growth regulators, i.e., 6-benzyladenine (BAP), gibberellic acid 3 (GA₃), and naphthalene acetic acid (NAA), prior to investigating the influences of explant types, media with or without vitamins, cultivars, and different phytohormones (BAP and GA₃). A high frequency of germination was observed in Murashige and Skooge (MS) medium with vitamins supplemented with 1 mg L^-1 BAP and 0.25 mg L^-1 GA₃. Cotyledonary node explants and Gamborg B5 with vitamins supplemented with 1 mg L^-1 BAP and 0.17 mg L^-1 GA₃ in callus induction medium (CIM) and 1 mg L^-1 BAP in shoot induction medium (SIM) were found to be the most efficient conditions for induction of soybean regeneration, both in callus development and shoot regeneration. Two Korean soybean cultivars, cv. Daepung and Nampung, showed similar development of shoot regeneration efficiency, but significantly different shoot induction times. Therefore, the protocol reported here may be used for further development of regeneration efficiency and can be employed for efficient transformation in soybeans.