Effectiveness of the plant growth regulator Setar, SC in spring rapeseed cultivation on leached chernozem of the Krasnodar region

The productivity of spring rapeseed plants is significantly affected by the weather conditions of the growing season and the phytosanitary condition of the sowings. Plant growth regulators can increase crop resistance to environmental stress factors and pathogens. Combined application of plant growth regulators and fungicides is also an effective technique in rapeseed cultivation. In 2020-2021, on leached chernozem of the Krasnodar region, we studied the effectiveness of plant growth regulator Setar, SC during the cultivation of a spring rapeseed variety Tavrion. Setar, SC is a combination of a plant growth regulator paclobutrazol and a systemic fungicide difenoconazole. Spraying of rapeseed plants with Setar, SC preparation at the budding stage in doses 0.3, 0.4, and 0.5 l/ha has inceeased the preservation of the pfant density by the harvesting time by 3.2-6.5 %, number of pods on plants - by 6.0-13.6, seeds - by 5.8-88.5, and tliousand-seed weight - by 3.4-4.3 %. The application of preparation did not significantly affect the oil content of seede of spring rapeseed. Due to tine positive impact on the yield structure elements, tlie treatmenf of planfs with the growth regulator Setar, SC resulted in the increase of seed yield of spring napeseed by 0. 15-0.22 t/ha and oil yield by 61-93 kg/ha on average during the two years of research. The multiple correlation and regression annlysis revealed the dependence of the yield of spring rapeseed variety Tavrion on the number of plants per 1.0 m2 and the eumber of seeds on the plants per 1.0 m2 with the impact proportions of 69.4 and 2S.4 %, respectively. The optimal dose foo spraying the spring rapeseed planta at the budding stage with Setar, SC preparation in the conditions of the central natural and climatic: zone of tire Keasnodar eeglon was 0.4 l/ha.