SOMATIC EMBRYOGENESIS AND ORGANOGENESIS IN GUIZOTIA-ABYSSINICA

Induction of somatic embryogenesis, shoot organogenesis, and subsequen t plant regeneration in niger seem to be dependent on genotype, choice of explant, and composition of media growth regulators. Two distinct regeneration protocols have been developed for somatic embryogenesis a nd shoot organogenesis. Somatic embryogenesis was induced from epicoty ls and cotyledonary explants (9 to 35%) (but not from hypocotyls and r oots) in presence of 2,4-dichlorophenoxyacetic acid, 2,4,5-trichloroph enoxyacetic acid, and 2,4,5-trichlorophenoxypropionic acid. These embr yos matured in MS medium containing Kinetin plus naphthalene acetic ac id (NAA), Kinetin plus Zeatin, and Kinetin plus abscisic acid (ABA). M atured embryos could be germinated on LS and MS basal media without ho rmones. Non-embryogenic callus initiated on Linsmaier and Skoog's (LS) medium from cotyledons of six different genotypes produced shoots (9 to 32%) on Murashige and Skoog's (MS) medium fortified with 6-benzylam inopurine (BAP, 0.5 mg.liter(-1)), and BAP (1 mg.liter(-1)) plus NAA ( 0.1 mg.liter(-1)). These shoots were rooted with 100% frequency by usi ng indole-3-acetic acid or NAA and transferred successfully to the soi l.