The dissertation provides a scientific justification and a new solution to the current scientific problem of justifying the improved selection of sunflower hybrids of different maturity groups for different growing conditions and the use of multicomponent multifunctional seed inoculation at reduced rates of fertilizers in order to increase the productivity and quality of sunflower seeds in the conditions of southern Ukraine.
The highest yields under stressful conditions among hybrids of the early ripeness group were obtained in Agora - 1.434 t/ha and Bella - 1.508 t/ha, and under favourable conditions in Cabana - 3.490, Bella - 3.590 and Niagara - 3.700 t/ha. The highest level of resistance to stressful conditions (RS) of the studied hybrids was characterized by Agora - 1.49. Andromeda and Niagara hybrids with values of 2.46-2.55 were the most unstable to stressful conditions. According to Sc, Agora and Bella hybrids with a value of 0.97 were distinguished, and according to Hom, Agora - 6.4 and Bella - 6.1. According to the regression coefficient (bi), hybrids of the intensive type Andromeda - 1.22 and Niagara - 1.29, stable type Agora - 0.71 and plastic type Bella - 1.02 and Latitude - 1.01 were identified.
The highest yields under stressful conditions among the hybrids of the medium early ripeness group were characterized by: Hysun 158 IT - 1.797 t/ha, Generalis - 1.676 and Isida - 1.674 t/ha, and under favorable conditions, the hybrid Fushia KC - 3.771 t/ha. Hysun 158 IT was characterized by the highest level of resistance to stressful conditions - 1.12, while Fushia KC and Gulfstream (2.32-2.34) were the most unstable. According to Sc, the hybrids Hysun 158 IT - 1.37, Generalis - 1.25 and Isida - 1.15 were distinguished, and according to Hom, the hybrids Generalis - 10.4 and Hysun 158 IT - 12.0. According to the regression coefficient (bi), the hybrids of intensive type Fushia KC - 1.27 and Electric - 1.28, stable type Generalis - 0.62 and Hysun 158 IT - 0.58, and hybrid of plastic type P63LE10 - 0.99 were distinguished.
The highest yields under stressful conditions among the hybrids of the mid-season group were obtained in Hysun 232 IT H0 - 1.615, P63LE113 - 1.470, Kondi - 1.348 and Alambra KC - 1.324 t/ha, and under favourable conditions - Hysun 180 IT - 3.580 t/ha, Hysun 238 - 3.510 t/ha, Bacardi - 3.592, Konstantin NS - 3,520 and Phenom 715 - 3,780 t/ha. The highest level of resistance to stressful conditions (RS) was characterized by the Anastasia hybrid - 0.73, while Hysun 238, Bacardi, Konstantin NS and Phenom 715 with values of 2.32-2.82 were the most unstable. According to Sc, hybrids PR64F66 and Alambra KC with a value of 1.60 were distinguished, and according to Hom, hybrids Hysun 180 IT - 11.0, Suberix - 11.1, Kondi - 12.0, Anastasia - 12.6, PR64F66 - 12.9 and Alambra KC - 14.5. According to the regression coefficient (bi), the hybrids of intensive type PR64F66 - 1.32 and Phenom 715 - 1.35, stable type Aromatic and Anastasia - 0.70 and hybrids of plastic type P63LE113 - 1.01 and P64LE25 - 1.03 were identified. According to σ2SACi, the most stable hybrids are Aromatic - 0.074 and Anastasia - 0.078, while hybrids Hysun 238 - 0.233, РR64F66 - 0.259 and Phenom 715 - 0.275 are unstable.
The highest yield under stressful conditions among the medium-late group was characterized by the hybrid Hysun 280 - 1.893 t/ha, and under favourable conditions - by the hybrid Hysun 298 - 4.010 t/ha. The highest level of resistance to stressful conditions was characterized by P64LP130 - 1.57, Hysun 189 Su - 1.68 and Hysun 254 - 1.69, and the hybrid Hysun 298 - 2.97 was the most unstable. According to Sc, Gf and Hom, the hybrid Hysun 280 was distinguished - 1.40, 2.77 and 10.2, respectively. According to the regression coefficient (bi), the hybrid of intensive type Hysun 298 was identified - 1.56, of stable type P64LP130 - 0.77 and Hysun 189 Su and Hysun 280 with a value of 0.80 and P64LE136 - 0.98, as a hybrid of plastic type.
According to the results of two experiments and adaptability indicators: the most intensive hybrid was Niagara, which means that the hybrid requires optimal growing conditions; Hysun 158 IT is the most stable hybrid, which means that the hybrid is optimally suited to limiting conditions; Hysun 280, Bella and P64LE136 are of the plastic type, which means that they are well adapted to various growing conditions.
Under optimal conditions, the highest seed price of 39650.84 UAH/ha and net profit of 18278.09 UAH/ha was obtained in the variant with N20P30 and polycomponent inoculation, and the low
