Effect of Fertigation with Urea-Ammonium Nitrate on the Seed Yield of Maize Maternal Lines

Fertilisation plays a crucial role in managing corn yields. Research conducted in 2021 − 2023 in the Central Forest-Steppe of Ukraine under unstable moisture conditions demonstrated the positive impact of urea-ammonia mixture (UAN) on the yield and sowing properties of maize maternal lines seeds across different maturity groups (P6/240, P5/320, P4/440). Applying 80 L/ha of UAN during the V10 (ВВСН 20) phase increased seed yield by 10.6 − 11.9% compared to the control. The highest seed yield was achieved with 120 L/ha of UAN, resulting in increases of 22.5% for P6/240, 21.3% for P5/320, and 16.4% for P4/440. However, increasing the UAN dose to 160 L/ha led to a slight decrease in yield for lines P5/320 and P6/240. Statistical analysis confirmed that fertilisers significantly influenced seed yield, accounting for 37% of the yield variance, with the genetic characteristics of the maternal lines contributing 34%. The positive effect of liquid nitrogen fertilisers on the 1,000-seed weight varied from 3.4% to 21.8%, depending on lines genetics and fertiliser dose.