Study into the effect of a chemical and a physical mutagens in combination in sunflower

The effects were studied of chemical and physical mutagens, i.e., of N-nitroso N-methyl urea, gamma radiation and both in combination, in sunflower. The maximum N-nitroso N-methyl urea concentration used in the experiment (1.0 mM) showed severe lethal effects under field conditions. The emergence rate of exposed seeds decreased with increasing ganma-radiation doses in all variants. Gamma radiation induced morphological changes. Flowering time was delayed in all exposed variants in comparison with the controls. In the M2 generation, no significant differences were found in the proportion of husks and in oil content. Significant differences occurred in the duration of the vegetation period, in plant height, and in the diameter of anthodium. (author)