Embryogenesis in vitro of several Citrus species and cultivars

Abstract

A number of experiments were performed to obtain somatic embryos and embryogenie cell lines from several species and cultivars of citrus by in vitro ovule culture. The source of ovules (pre-anthesis and post-anthesis), incubation conditions (light and darkness) and several modifications of the culture medium were evaluated. All the species and cultivars assayed produced somatic embryos and “pseudobulbi”, but production of friable embryogenie callus was species dependent. The small proliferation of callus and globular bodies recovered from the primary cultures were suitable for recovering embryogenie callus lines by periodical subculturing into fresh medium. After several monthly subcultures discarding embryos and “pseudobulbi”, cell lines virtually devoid of organized structures were obtained from three cultivars of sweet orange, sour orange and Cleopatra mandarin. In all these species, embryogenesis was restored spontaneously and/or by substitution of sucrose by maltose or lactose in the culture medium. The embryos germinated and produced phenotypically normal plants.