The influence of biological products on the growth and development of sunflower plants (Helianthus annuus L.) in the northern steppe of Ukraine
To neutralize negative factors (excessive technogenic load, deterioration of water, nutrient regime, and humus state of the soil) and improve the nutritional system of sunflower plants, it is necessary to use more widely mineral, organic, and micronutrient fertilizers, plant growth regulators. Thanks to the regulatory mechanisms of biological products, the development of the leaf surface are enhanced, the main functions are essential for the life of sunflower plants, and they are activated by: membrane processes, cell division, respiration and nutrition, the activity of enzyme systems, photosynthesis, a branched root system with enhanced absorbing capacity is created at the growth period. The main goal of this work was to study the influence of the growth of regulatory substances, different in the direction of action, on the morphogenesis, growth, and development, and productivity of sunflower plants of different ripeness groups in the conditions of the Northern Steppe of Ukraine. Moreover, the determination of the most rational stimulants of the growth of sunflower plants, which ensure the resistance of plants to diseases and adverse environmental factors, optimal growth and development of plants, and contribute to obtaining high and sustainable yields of oilseed crops. The laying and carrying out of field experiments was carried out following the generally accepted methodology of experimental work. The experimental part of the work was performed during 2018–2020 on the scientific and research field of the National Scientific and Research Center of Dnipro State Agrarian and Economic University in the stationary experiment of the Plant Science Department in five-crop rotation pure steam – winter wheat – corn – barley – sunflower to study the effectiveness of modern elements in technologies for growing cereals, legumes, and oilseeds. Scientific studies have established that the formation of the maximum leaf surface area of sunflower was observed using the growth stimulant Tseron (0.5 L/ha) to 70.9–78.1 thousand m2/ha, or 5.5–10.2% more for control. Here, sunflower plants formed the largest diameter of the basket – 23–26 cm (11.5–30.4% more than the control), and the maximum number of seeds in 829–951 pcs. The highest weight of 1000 seeds was characteristic of the medium-early hybrid Sumico HTS – 54.0–60.0 g, and the lowest for the medium-late Subaro HTS – 51–55 g, due to the biological characteristics of the hybrids. Plant growth stimulants on sunflower contributed to an increase in crop yields 1.01–1.7 times. The most significant increase in grain for all hybrids was provided by the agent Tseron (0.5 L/ha) – 0.16–0.75 t/ha, or 8.2–43.3%. The application of restricted drugs Tseron (0.5 L/ha) and Architect (0.5 L/ha) contributed to the growth of oil content by 3–8 and 4–6 percentage points.