SOMATIC EMBRYOGENESIS IN CELL SUSPENSION CULTURE OF COWPEA (VIGNA UNGUICULATA (L.) WALP)

ABSTRACT Embryogenic callus was induced from seedling leaf explants of cowpea (Vigna unguiculata (L.) Walp. cv. C152 on Murashige and Skoog (MS) medium containing 2.0 mg 1−1 2,4-dichlorophenoxyacetic acid (2,4-D). The maximum frequency of somatic embryogenesis was noticed when this callus was transferred to MS liquid medium supplemented with 2 mg 1−1 2,4-D. Further studies on ontogeny of somatic embryos showed that the cells destined to become somatic embryos divided into spherical or filamentous proembryos. Subsequent divisions in the proembryo led to globular, heart, torpedo-shaped, and cotyledonary-stage somatic embryos. Tiny plantlets were obtained by transferring the cotyledonary-stage somatic embryos to MS liquid medium containing 0.5 mg 1−1 2,4-D.