Effects of kanamycin on tissue culture and somatic embryogenesis in cotton

The aminoglycoside antibiotic kanamycin was evaluated for its effects on ca llus initiation from hypocotyl and cotyledon explants, proliferation of non -embryogenic and embryogenic calli, initiation and development of somatic e mbryos in cotton (Gossypium hirsutum L.). On this basis, the potential use of kanamycin as a selective agent in genetic transformation with the neomyc in phosphotransferase II gene as the selective marker gene was evaluated. C otton cotyledon and hypocotyl explants, and embryogenic calluses were highl y sensitive to kanamycin. Kanamycin at 10 mg/L or higher concentrations red uced callus formation, with complete inhibition at 60 mg/L. Kanamycin inhib ited embryogenic callus growth and proliferation, as well as the initiation and development of cotton somatic embryos. The sensitivity of embryogenic callus and somatic embryos to kanamycin was different during the initiation and development stages. Kanamycin was considered as a suitable selective a gent for transformed callus formation and growth of non-embryogenic callus. Forty to sixty mg/L was the optimal kanamycin concentration for the induct ion and proliferation of transformed callus. The concentration of kanamycin must be increased (from 50 to 200 mg/L) for the selection of transformatio n embryogenic callus and somatic embryos. A scheme for selection of transge nic cotton plants when kanamycin is used as the selection agent is discusse d.