ABSTRACT
Callus induction and subsequent somatic embryogenesis using mature cotton plants would allow tissue culture selection and clonal propagation of defined phenotypes. Stem, leaf, and petiole sections were excised from nature cotton (Gossypium klotzschianum Anderss.) plants and surface sterilized. Stem and petiole explants were cut into 10 mm long segments and sliced longitudinally. Leaf tissue was trimmed to 10 mm by 10 mm with the midvein included. Petiol and stern sections produced a rapidly growing, green callus if oriented with the epidermis in contact with the culture medium. Petiole and stem sections with the culture surface in contact with the culture medium and leaf tissue with any orientation either browned or produced a slow growing red callus. The green callus was subcultured biweekly and has been maintained for 8 months. Somatic embryos were obtained following transfer of the callus to a liquid medium containing the auxin, 2,4-dichlorophenoxyacetic acid (2,4-D). These embryos were initiated and underwent early development on clumps of callus tissue. Agitation of the cultures caused larger embryos to detach from these callus clumps. Following removal of 2,4-D from the culture medium, the embryos matured and were placed on numerous media to induce germination.
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