It is shown that the use of plant growth regulators of antioxidant action for presowing treatment of
oilseed crops can both oppress and stimulate germination processes.
The plant growth regulator caused the activation of the growth process, which was particularly
manifested through the height of plants and stem diameter. The increase in the leaf surface area of the
crop by 39.3 % was defined by plant growth regulator and greatly depended on rainfall (r = 0.999) during
the period of 00 65 on BBCH scale. Medium correlation (r = 0.588) was determined between rainfall
in the phase of rapid growth and inflorescence diameter. Growth regulator affected the yield
of sunflower significantly the share of a factor in the formation of yield was 32.7 %. The share of the
impact of water deficit was 58.4 % on average over the years of research. Pollen fertility and seed
emptiness of sunflower depended on relative humidity during flowering – r = 0.990 for the control plants
and r = 0.973 in case of AKM application. The weight of 1000 seeds increased under PGR action by an
average of 17 33 % depending on the zone of the inflorescence. In general, hybrids and plant growth regulator as researched factors significantly affect the yield
of sunflower but the proportion of influence of hybrid (factor A) (85.1 %) is significantly higher than that
of the impact of PGR (factor B) (7.5 %). This should be considered when developing anti-stress
techniques in technologies of sunflower cultivation in the Steppe zone of Ukraine. Correlation of high
strength was found between leaf surface area and rainfall (BBCH - 00-65) for all of hybrids (r = 0.868 –
0.996). AKM showed the greatest influence on the yield of sunflower plants of Zubr and Forvard hybrids,
where fluctuation was within 14.3 - 31.3