II. The effect of various doses of gamma 60Co radiation upon some morphological features of China aster (Callistephus chinesis Nees) in M1 and M2 generations

Abstract

The present paper discusses the effect of antecedent gamma radiation upon 4 varieties of China aster in M<sub>1</sub> and M<sub>2</sub> generations. Studies were undertaken on the effect of various doses of radiation upon the following features : height of plants, maximal length of ramification of the Ist order, diameter of inflorescence, and number of set inflorescence. In M<sub>1</sub> generation (plants from irradiated seeds) negative effect of radiation was noted in almost all features under study, usually the greater the radiation dose. Only in case of two varieties ('Agnieszka' and 'Goplana') positive effect of irradiation upon plant height was noted, at radiation dose of 3 kR. However, further increase of radiation dose was harmful also for these two varieties. In M<sub>2</sub> generation (progeny of irradiated plants) the effect of gamma radiation upon most features under study was beneficial - in most cases stimulation overbalanced rare symptoms of depression. Reaction was different in all varieties under study.