V. Indukowanie promieniami gamma 60Co zmienności modyfikacyjnej i mutacji u astra chińskiego (Callistephus chinensis Nees) [V. Induction with 60Co gamma rays of modification variability and mutation of China aster (Callistephus chinensis Nees)]

Abstract

The effect of radiation on variability was investigated in plants of five varieties of China aster, grown from seeds pretreated with various doses of gamma rays (generation M₁) and in the progeny of these plants (generation M₂). Both in generation M₁ and in M₂ the frequency of occurrence of radiation induced changes varied. In the M₁ generation, beside teratological changes found most frequently in early periods, the observed variability concerned mostly leaves, their colour and size and the form of the lingual flowers. Plants with a different colour of flowers or a different habit were only sporadic. The changes induced by radiation were more frequently observed in the M₂ generation than in the M₁ They involved the following characters: height and habit of plants, colour of shoots, leaves and flowers, the forms of lingual marginal flowers, the time of flowering and the perfume. Most frequently changes were observed in several characters. When the shoots and leaves colour showed changes of anthocyanin type, the colour of the flowers was usually also modified. Most changed plants were noted after a dose of 9 kR in the M₁ generation, and after 6-9 kR in the M₂ generation. These doses were described in generation M₁ at the stage of flowering in most of the tested varieties as LD₅₀.