The biostimulants effectiveness in growing sunflower hybrids of different maturity groups in the Western Forest-Steppe conditions

Abstract

Aim. To establish the influence of the latest plant growth regulators on the formation of yield and to determine the economic efficiency of growing modern sunflower hybrids of different maturity groups in the conditions of the Western Forest-Steppe. Methods. Field, calculation, statistical. Results. The differential contribution of two factors – genetic characteristics of hybrids with different ripening periods and the use of growth regulators – to the formation of sunflower yield increases was determined. The level of sunflower seed yield depended on the growth regulators use and genetic characteristics of hybrids, and ranged from 3.27 to 3.98 t/ha. The productive potential increased with the extension of the growing season, which is consistent with the biological ability of later hybrids to more effectively accumulate nutrients and reuse plastic substances. The effect of growth regulators was appeared differently depending on the formulation and the maturity group. The maximum effect was provided by the Phytospectr (0.43–0.45 t/ha or 12.6–12.7 %), which indicates a complex effect on physiological and biochemical processes in plants. A pronounced synergism of maximum realization of the high genetic potential of the hybrid under conditions of optimized regulation of growth processes was established: in the mid-ripening hybrid P64LE280, the total effect reached 0.58 t/ha (17.7 %) when using Phytospectr, while in the mid-late P64LE162 – 0.71 t/ha (21.7 %). The highest economic indicators were obtained with a double application of the Fitospectr: the cost of production – from 102.5 to 111.4 thousand UAH/ha, conditional net profit – 61.8–70.8 thousand UAH/ha, the level of profitability – 151.9–173.9 %. Conclusions. In the conditions of the Western Forest-Steppe, the use of plant growth regulators in critical phases of growth and development of modern sunflower hybrids is agronomically expedient and economically justified. The significance of factors increases in the following order: genetic features of the hybrid, the action of growth regulators, the interaction of the genotype and the growth stimulator. The highest efficiency was achieved by combining the technology of growing a medium-late hybrid with a double application of the Phytospectr on the background of N60P60K60, which ensures a crop yield of 3.98 t/ha, obtaining 70.8 thousand UAH/ha of conditional net profit with a profitability of 173.9 %.