Purpose. To study the effect of AKM plant growth regulator on growth, development and yield formation of sunflower (Helianthus annuus L.) hybrids in hybridization plots under the conditions of the Southern Steppe zone of Ukraine. Methods. Laboratory tests, field study, statistical evaluation. Results. The results of studies devoted to determining the optimal AKM concentration for the treatment of seeds of the maternal and paternal lines, the effect of AKM on field germination, biometric parameters of sunflower plants, seed quality (F1) and yield are presented. Three hybrids of the Ukrainian selection, such as ‘Alpha’, ‘Logos’ and ‘Persei’ were studied during 2014–2016. Optimal concentration of AKM (0.0015 g/l) was defined. The vigor of seeds processed by AKM was higher than in check variety by 0.8–12.8 р.р. (♂); 0.4–10.7 p.p. (♀), laboratory germination – by 2.3–6.1 p.p. (♂); 3.5–6.2 p.p. (♀). In 2016, the sunflower plant height for all variants exceeded this parameter to be obtained for other years of the study. This could be explained by the fact that HTC in 2016 for the BBCH 00–39 period was 1.4 times higher than in 2015. In general, hybrids as the studied factor considerably influenced sunflower yield, and the share of the hybrid (factor A) influence is 33%. This should be considered when selecting hybrids for sunflower cultivation technologies in the Steppe zone of Ukraine. Conclusions. Hydrothermal conditions of the year had the maximum impact on the formation of seed quality and yield of sunflower plants of the hybrids under study, but when using AKM growth regulator for presowing seed treatment, this negative impact was reduced by an average of 23%.