Elements of plant productivity and biological yield capacity of grain sorghum hybrids depending on the inter-row width and seed sowing rate

Sorghum is one of the most important food, fodder, and energy crops in the world. The crop is resistant to stress factors, especially moisture deficiency. This biological feature allows it to form high and stable grain yields in conditions of moisture deficiency and hot temperature. Grain sorghum has a significant advantage in terms of several physiological, biological, yield characteristics compared to other crops, but the acreage under it in Ukraine stays limited. The main reason for this is, first, the lack of varietal technologies for its cultivation with improved elements. Therefore, the study of the complex influence of the rate of sowing seeds and the width of the row spacing on the formation of productivity elements is currently a relevant area of research. The main goal of the research was to study the influence of a complex of factors: row spacing, seed sowing rates on the productivity and biological yield of sorghum grain. The research was carried out in 2019-2021 at FE “Diunis”, Kreminskyi district, Luhansk region. The scheme of the experiment: width between rows - 35, 45 and 70 cm, hybrids - Swat and Flagg, sowing rates - 100,000 pieces/ha, 140,000, 180,000 and 220,000 pieces/ha. The Flagg hybrid formed a higher panicle productivity of the main and side stem systems. As to sorghum hybrid Flagg, the grain mass from panicle of the main and lateral stems was 45.1 and 39.0 g, respectively; that of hybrid Svat were 39.5 and 31.1 g. A higher panicle productivity of hybrid Flagg was formed due to a much larger mass of 1,000 grains (by 35–40 %); sorghum hybrid Svat had a larger number of grains in panicle of both stem systems. The biological grain productivity of both stem systems was higher for sorghum hybrid Flagg – 5.87 t/ha, as compared with that of early-ripening hybrid Svat, which was equal to 4.75 t/ha