Adventitious Shoot Formation from Hypocotyl Sections of Mature Soybean Seeds.

A new system for simple and efficient shoot regeneration of soybean (Glycine max (L.) merr.) is reported using the hypocotyl of mature seeds. Two transverses of 1-mm sections of the hypocotyl were cut from mature seeds: sections containing a cotyledonary node and sections 1 to 2 mm from the cotyledonary node. The effects of thidiazuron (TDZ) concentrations, plating methods, and genotypic differences were examined. Shoots were formed from cotyledonary node ends in all conditions examined. Meanwhile, shoots were formed from the ends of hypocotyl sections on B5 media containing TDZ. The optimal TDZ concentration for organogenesis was 2~10 μM. The efficiency of organogenesis varied with the method of plating of explants. The ends of the hypocotyl sections in contact with the media only produced adventitious shoots. Adventitious shoots were formed effectively by placing explants on the media oriented so that the hypocotyl axes were perpendicular to the surface of the media. The efficiency of organogenesis differed with the position of the hypocotyl ends. It was important to use the ends that were 1 mm from the cotyledonary nodes. Genotypic differences were observed in the organogenesis of the hypocotyl ends.