Formation of biometric indicators and yields of winter wheat of varieties Lutescens and Erythrospermum under different seeding standards in the conditions of the Northern Steppe of Ukraine

Goal. To determine the influence of the norms of sowing winter wheat of varieties Lutescens and Erythrospermum on the adaptation of plants to the arid conditions of the Northern Steppe of Ukraine, and the formation of grain yields. Methods. Norms of wheat sowing of winter varieties Vezha (Lutescens) and Yuzovska (Erythrospermum) in the range from 1.5 to 6.5 million pcs. of germinating seeds per 1 ha were studied in 2021–2024. Laboratory, field, computational, and mathematical statistical methods were used. Results. It was established that seeding standards significantly influenced the development of winter wheat plants in the first stages of development. The lowest plants were for sowing 1.5 million pcs./ha (Vezha — 13.4 cm, Yuzovska — 13.5 cm), and the highest — for sowing 6.5 million pcs./ha (Vezha — 14.1 cm, Yuzovska — 14.3 cm). Plants of winter wheat of both varieties at seeding rates of 1.5 million pcs./ha demonstrated the highest indicator of the coefficient of productive shrubbery: Vezha — 2.9, Yuzovska — 2.4. Seeding rates significantly affected the chlorophyll content, reducing its amount proportionally with an increase in seeding rate. The highest level of productivity of wheat of the Vezha variety was provided by the seeding rate of 4.5 million pcs./ha (6.2 t/ha); for the Yuzovska variety, it was the rate of 3.5 million pcs./ha (6.9 t/ha). The lowest productivity levels of the Vezha variety — 4.6 t/ha (16.4% less compared to the control) and the Yuzovska variety — 5.1 t/ha (17.7% less compared to the control) were obtained by sowing 1.5 million pcs./ha. Conclusions. In the arid conditions of the Eastern part of the Northern Steppe, winter wheat plants of both varieties had the highest coefficient of productive shrubbery at the seeding rate of 1.5 million pcs./ha. The highest yield of wheat of the Vezha variety, namely 6.2 t/ha, was observed at seeding rates of 4.5 million pcs./ha. The yield of wheat of the Yuzovska variety increased from 4.6 to 6.9 t/ha with an increase in seeding rates from 1.5 to 3.5 million pcs./ha.