Nitrogen enhances seed oil, tocopherols, seed yield, and seed quality in onion

Nitrogen is an important nutrient known for enhancing biomass and grain yield. Nevertheless, the effect of varying nitrogen treatment rates on the tocopherol levels in onion seeds remains poorly understood. The purpose of this study was to ascertain how the different rates of nitrogen fertilization affected the seed yield, seed quality, oil content, and tocopherol content in onion seed. A field experiment was carried out for two years, i.e., 2020–21 and 2021–22. The onion seeds crop was fertilized with different nitrogen levels, i.e., 0 kg/ha, 50 kg/ha, 100 kg/ha, and 150 kg/ha. Nitrogen application had a significant effect on seed oil content and quality parameters like α, β, γ, δ and total tocopherol content. Further nitrogen applied at 100 kg/ha had a favourable effect on the seed yield and seed quality parameters. These results demonstrate that nitrogen fertilization improves both the quantity and seed oil and quality of onion seeds, highlighting its significance in enhancing onion seed yield and quality.