Вплив норм висіву на біометричні показники та врожайність нових гібридів соняшнику

Plant density and fertilization regimens are considered as important elements of the sunflower hybrid cultivation technology. The purpose of this study was to evaluate the effect of seeding rates and mineral fertilizers on biometric parameters and seed yield of new zoned sunflower hybrids in the Eastern Forest-Steppe of Ukraine. The study was conducted in an experimental field of the Yuriev Plant Production Institute of NAAS of Ukraine in 2021 and 2023. We studied two classic oil sunflower hybrids (‘Yarylo’ and ‘Khoryv’), two fertilization regimens (without fertilization (control) and N30P30K30), and four seeding rates (40,000, 50,000, 60,000, and 70,000 germinable seeds per 1 ha). The tallest plants (165.8 cm) were recorded for hyb. ‘Khoryv’ sown at a seeding rate of 70,000 seeds/ha in the control and the shortest ones – for hyb. ‘Yarylo’ (139.2 cm) sown at the seeding rate of 60,000 seeds/ha hybrid and fertilized with N30P30K30. The mean number of leaves per plant was greater in hyb. ‘Khoryv’ (31.2 leaves) than in hyb. ‘Yarylo’ (30.4). The maximum leaf area per plant and per hectare was formed by hyb. ‘Yarylo’ sown at the seeding rate of 40,000 seeds/ha and fertilized with N30P30K30P30K30 (9,425.6 cm2 and 39,500 m2, respectively). Hyb. ‘Yarylo’ yielded more seeds when sown at the seeding rates of 40,000 seeds/ha and 50,000 seeds/ha, especially after N30P30K30 fertilization (2.07 t/ha and 2.02 t/ha, respectively). Hyb. ‘Khoryv’ yielded more seeds in the control when sown at the seeding rate of 70,000 seeds/ha (2.19 t/ha) and in the N30P30K30 experiment when sown at the seeding rate of 40,000 seeds/ha (2.24 t/ha). Therefore, the sunflower plant height, number of leaves, leaf area, and seed yield depended on hybrid features, fertilization, and plant density.