Effect of high-energy ionizing radiation on the DNA content and genetic variation in chrysanthemum plants regenerated from irradiated ovaries

This study aimed to evaluate the range of quantitative and qualitative genetic changes in chrysanthemum plants regenerated in vitro from ovaries irradiated with high-energy photons (5, 10, and 15 Gy) and high-energy electrons (10 Gy). The highest DNA loss (up to 11%) was observed in plants originating from ovaries treated with 10 Gy high energy. AMOVA revealed significant differences between populations of plants representing different mutagenic treatments (18% for RAPD-based and 22% for SCoT-based analysis). The incidence of genetic changes was strongly correlated with the applied type and dose of ionizing radiation. The highest genetic distances to reference plants were observed for plants regenerated from 15 Gy high-energy photon (5.8% with RAPD and 1.7% with SCoT) and 10 Gy high-energy electron-treated explants (6.0% with RAPD and 2.9% with SCoT). Considerable changes in the phenotype of mutants were not necessarily correlated with the extent of genetic alterations. Qualitative and quantitative methods of evaluating post-radiation genetic changes should be combined for reliable detection of variant plants at early developmental stages.