NEW CHRYSANTHEMUM CULTIVARS AS A RESULT OF in vitro MUTAGENESIS WITH THE APPLICATION OF DIFFERENT EXPLANT TYPES

Induced mutagenesis allows to obtain in relatively short time new cultivars of chrysanthemum differing in single characteristic traits such as the colour or shape and size of inflorescence, which determines their decorative values. The traditional breeding methods as crossing, selection and techniques of genetic transformation face limitations in this species. The object of investigation were three cultivars of Chrysanthemum x grandiflorum (Ramat.) Kitam. - 'Albugo', 'Alchimist', 'Satinbleu'. Gamma radiation in dose of 15 Gy was obtained from Co-60 cobalt source generated by Theratron 780 C. The dose rate was 2.14 Gy x min(-1). 'Albugo' and 'Satinbleu' microcuttings cultured on MS medium were exposed to irradiation. Following the irradiation, single-node explants and leaves were excised from plantlets and subcultured onto MS medium supplemented with 0.6 mg x dm(-3) BAP and 2.0 mg x dm(-3) IAA. In 'Alchimise there were irradiated leaf explants with callus regenerated on petioles. A month earlier this explants were placed on the MS medium with 0.6 mg x dm(-3) BAP and 2.0 mg x dm(-3) IAA added. The regeneration of adventitious shoots was conducted without subculturing onto fresh medium. Newly formed shoots were transferred onto rooting medium 4 months after the irradiation. Gamma radiation effected the regeneration of shoots on explants. From the mutants obtained in vM(2) generation the most interesting, worth introducing to cultivation five genotypes were selected: 'Albugo Sunny', 'Alchimist Tubular', 'Alchimist Golden Beet', 'Satinbleu Minty', 'Satinbleu Honey'.