Plant regeneration via somatic embryogenesis from protoplasts of six explants in Coker 201 (Gossypium hirsutum)

Fertile regenerated plants were obtained from protoplasts via somatic embryogenesis in Coker 201 ( Gossypium hirsutum L.). Protoplasts were isolated from six different explants: leaves, hypocotyls, young roots, embryogenic callus, immature somatic embryos and suspension cultures and cultured in liquid thin layer KM8P medium. Callus-forming percentage of 20 - 50% was obtained in protoplast cultures from embryogenic callus, immature embryos and suspension cultures, and visible callus formed within 2 months. Callus-forming percentage of 5 - 20% in protoplast cultures from young roots, hypocotyls and leaves, and visible callus formed in 3 months. NAA 5.371 mu M/ kinetin 0.929 mu M was effective to stimulate protoplast division and callus formation from six explants. Percentage of callus formation in the medium with 2,4-D 0.452 mu M/ kinetin 0.465 mu M was over 40% from suspension cultures and immature embryos, 25% from embryogenic callus and 10% from hypocotyls. Callus from protoplasts developed into plantlets via somatic embryogenesis. Over 100 plantlets were obtained from protoplasts derived from 6 explants. Ten plants have been transferred to the soil, where they all have set seeds.