Comparative study of somatic embryogenesis from immature and mature embryos and organogenesis from leaf-base of Triticale

Immature and mature zygotic embryos of hexaploid, Triticale var. DT-46 form ed an embryogenic callus, with subsequent somatic embryo formation upon sub culture to MS (Murashige and Skoog, 1962) or N-6 (Chu et al., 1975) nutrien t medium supplemented with various concentrations (9.0-22.5 muM) of 2,4-dic hlorophenoxyacetic acid (2,4-D). Of the two types of explants, embryogenic tissue from immature embryos responded at a higher frequency, to form somat ic embryos over the callus surface. Leaf-base segment cultured on to 2,4-D- containing medium formed a tissue which did not form somatic embryos and in stead differentiated into shoot-buds. N-6 medium proved to be more effectiv e than MS in support of somatic embryogenesis or shoot-bud formation. Regen eration of plantlets occurred on 2,4-D-free basal medium. These in vitro-fo rmed plantlets were successfully transferred to soil and set seed.