Effects of proliferation, maturation, and desiccation methods on conversion of soybean somatic embryos

Germination of soybean [Glycine max (L.) Merrill] somatic embryos and conversion to whole plants are generally low. This study was conducted to investigate the effects of proliferation, maturation, and desiccation methods on conversion of soybean somatic embryos to plants. Soybean cv. Jack somatic embryos, proliferated on a solid medium containing 90.5 μM (20 mg l ^-1) 2,4-dichlorophenoxyacetic acid (2,4-D) (MSD20), showed a regeneration rate significantly higher than those proliferated in a liquid medium containing 45.25 μM (10 mg l^-1) 2,4-D (FN Lite). When a liquid medium without 2,4-D and B5 vitamins (FN Superlite) was used for maturation, the duration of time necessary for embryo development could be shortened by more than a month compared to maturation on a standard solid medium (MSM6AC). An air-drying method, in which somatic embryos were desiccated in an empty sealed Petri dish for 3-5 d, gave rise to the best germination efficiency among the four desiccation methods tested: fast, slow, air, and KCl methods. The final percentage of moisture seems important since embryos over-dried by the fast and slow methods did not convert well into plants.