Increasing the yield and grain quality of grain sorghum hybrids in the Southern Steppe zone of Ukraine

Goal. To determine the optimal sowing dates and plant density in the agrocenosis of grain sorghum hybrids to increase the yield and quality of its grain in the Southern Steppe zone of Ukraine. Methods. Field — to study the influence of various factors on the growth, development, and grain yield of grain sorghum hybrids; laboratory — to determine the quality indicators of the culture, in particular, the content of protein and starch in the obtained culture samples; tabular — to systematize, organize and display information; graphic — to visualize the obtained data. The scientific research program included the study of the basic elements of grain sorghum hybrid cultivation technology and their influence on phenological and biometric indicators, adaptive properties of plants, the phytosanitary status of crops, seed productivity, and quality indicators of culture. From the quality indicators of sorghum grain, the content of protein (method of mineralization with sulfuric acid in the presence of a catalyst according to Stein-Moore) and starch (method of dissolution in a hot solution of hydrochloric acid with subsequent study on a polarimeter) was studied. Results. During the years of research, the maximum grain yield (6.54–6.69 t/ha) was characterized for hybrids of grain sorghum Sontsedar and Dash E at an early sowing period and plant stand density of 140–180 thousand plants/ha. During the late sowing period, these hybrids produced the highest productivity — 4.0 t/ha at stand densities of 180 and 220,000 plants/ha. The use of a 0.01% solution of succinic acid as a growth stimulator in the panicle formation phase of the culture ensured an increase in the yield of grain sorghum hybrids by 12–15% and accelerated grain ripening by 7–8 days. Conclusions. It is recommended to sow grain sorghum at a soil temperature of 8–10°C and seed wrapping depth of 2–4 cm, which will contribute to optimal seed germination and development. For hybrids Sontsedar and Dash E, it is recommended to form a density of plants in the agrophytocenosis of 140 and 180 thousand plants/ha, respectively. Under unfavorable agro-climatic conditions, late sowing is recommended. For this, the Dash E hybrid is sown at a density of 180,000 plants/ha at a soil temperature of 14–16 °C. It is proposed to use a solution of succinic acid as a growth stimulator during the formation of the inflorescence of the crop, which will make it possible to increase grain productivity by 0.6–0.7 t/ha. These recommendations are based on experiments and practical experience and can be useful for agricultural enterprises specializing in the cultivation of grain crops in the conditions of the Southern Steppe of Ukraine.