Growth, development, and formation of corn hybrids’ plants of different ripening groups depending on plant stand density

Abstract

The study was conducted as to establishing the conformities to the natural laws of agro-ecosystems’ structure of modern corn hybrids belonging to various ripening groups depending on plant stand density, at which the maximal manifestation of their productivity genetic potential is achieved. The research was conducted during 2019–2021 in field conditions on the farm of Shylivka village council, Poltava region. Modern corn hybrids of three ripening groups were taken as materials for the investigation: Belami early-ripening, Tonifi KC mid-early-ripening, and Poesi KC mid-ripening. The study of phenological characteristics has shown that the duration of inter-phase periods and the crop vegetative period almost did not change under the effect of plant stand density (only on 1–2 days), but depended on the hybrids’ biological characteristics and weather conditions. It has been determined that plant height indicator depends on weather conditions of the corn vegetative period, but not only on the hybrid’s seeding density and its biological peculiarities. The highest indicators of linear growth were fixed in the plants of Belami hybrid at the density of 75 thou/ha (193.1 cm), Tonifi KC – 70 thou/ha (226.2 cm), and Poesi KC – 75 thou/ha (227.9 cm). It has been found that during the research years, overcrowding of sown areas leads to increasing the height of ear attachment in all the studied hybrids, which, on the average, was by 4.6 % more for Belami (at the density of 65–85 thou/ha); for Tonifi KC – by 4.4 % (at the density of 60–80 thou/ha); and by 4.2 % for Poesi KC (at the density of 65–85 thou/ha). Also, the height of ear attachment depends on plant height, and it is the largest in Poesi KC hybrid (88.3–92.2 cm) and the minimal in Belami (82.5–86.5 cm). In case of overcrowding, corn ear linear sizes decreased from the minimal to the maximal in Belami – by 3.4 %, Tonifi KC – by 5.5 %, Poesi KC – by 7.3 %, and grain weight per ear – by 12.1, 15.6, and 20.4 %, respectively. According to the obtained results, the optimal plant stand density of the studied hybrids was determined for receiving the maximal yield: 75 thou/ha for Belami, 70 thou/ha for Tonifi KC, and 75 thou/ha for Poesi KC.