REGENERATION SYSTEMS FROM IMMATURE EMBRYOS OF BULGARIAN PEA GENOTYPES

Ten genotypes from Pisum sativum and Pisum arvense were screened for t heir regeneration abilities. Most of them were created through experim ental mutagenesis from Bulgarian varieties and have various valuable a gronomic traits. Embryonic axes from immature embryos were plated on m odified Murashige and Skoog medium, containing different concentration s of 2,4-dichlorophenoxyacetic acid (2,4-D), alpha-naphthaleneacetic a cid (NAA) and benzyladenine (BA). Two schemes for direct and indirect organogenesis were established. Callus and shoot formation were induce d on media containing 0.2 mM 2,4-D or 5 mM BA, respectively. Embryonic axes formed buds directly when plated on medium with 10 mM BA and 1 m M NAA. Organogenesis and adventitious bud formation were maintained on medium supplemented with BA and NAA. Rhizogenesis was induced on Gamb orgs' B5 medium. All screened genotypes were able to regenerate plants with a high efficiency (50-100%) although some differences in their o rganogenetic response were observed.