Male sterility in sunflower (Helianthus annuus L.) induced with new gametocidal agents

Aim. Evaluation of the new gametocidal agents effect on pollen sterility and viability of female gamethophyte in sunflower was the main goal ofthe investigation. Methods. Sunflower florets were treated with nine newly synthesided in the Institute of Bioorganic Chemistry and Petrochemistry of NAS of Ukraine chemicals in concentrations ranged from 1.0 ml/l to 15.0 ml/l of stock solutions. Gibberellic acid (50 mg/l) was used as a control. The gametocidal effect on the pollen sterility was determined using seed-set after gametocide treatment and controlled self-pollination compared to untreated florets. Influence of gameticides on the female gametophyte viability was evaluated as seed-set after free cross-pollination. Results. It was revealed that DGK-2 and DGK-3 have a high gametocidal activity even at the lowest dose – 1 ml/l. DSK-10 appeared to be the most effective one at a dose of 5 ml/l. This treatment allowed us to achieve near-complete male sterility. Negative effect of gametocides on the female gametophyte was enhanced with increase in their concentrations. However, new gametocides had less negative effect compared to gibberellin in certain experimental variants. Conclusions. DGK-2, DGK-3 and DSK-10 are promising for further investigations on the chemical demasculation in sunflower for further hybridization on the fertile basis without mechanical anther removal. Keywords: sunflower, (Helianthus annuus L.), induced pollen sterility, gamitocidal agents, gibberellin, seed-set.