Mutations induced in spring barley by gamma rays applied during different phases of plant development. Part 1. Radiosensitivity of two cultivars irradiated during different stages of organogenesis

Plants of Damazy and Lubuski spring barley cultivars were subjected to gamma irradiation of 60Co during twelve stages of organogenesis. Doses of 0.25 to 10 kR were applied. The highest radiosensitivity of plants was found during the first stages of growth and development (1-6) and during gametes formation (stage 7-8) up to the end of heading. Irradiation of 0.25 to 2 kR of plants at 1-7 stages of organogenesis caused little decrease in seed setting (42-100% plants formed seeds). Higher doses of irradiation, 3-4 kR, strongly affected seed setting - only 3-46% plants produced seeds. Doses still higher were lethal. Viability of plants irradiated during 8-9 stages of organogenesis was higher since majority of plants formed seeds after irradiation with doses up to 4 kR. Even the dose of 10 kR applied at these stages was not lethal, 52-94 per cent of plants produced seeds. No differences in radiosensitivity between two tested cultivars were observed. (author)