نوع مقاله : مقاله کامل علمی- پژوهشی
نویسندگان
گروه مهندسی تولید و ژنتیک گیاهی، دانشکده کشاورزی، دانشگاه شهید چمران اهواز، اهواز، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: Sesame is a valuable crop in tropical and subtropical regions, requiring warm conditions during its growth period for optimal yield. Although classified as a low-input crop with minimal fertilizer requirements, nitrogen availability directly impacts its productivity. Given the importance of the issue to study the phenological evaluation and determination of nitrogen use efficiency in advanced New Shatter-Resistant Sesame Cultivars this experiment was conducted.
Materials and methods: A two-year field study (2021–2022) was conducted in northern Khuzestan to evaluate phenology and nitrogen use efficiency (NUE) in new shatter-resistant sesame varieties under varying nitrogen regimes. The experiment followed a split-plot arrangement within a randomized complete block design with four replications. Main plots received urea fertilizer at three levels: 100, 150, and 200 kg ha⁻¹ (46, 69, and 92 kg pure N) in 2021, and 150, 200, and 250 kg ha⁻¹ (69, 92, and 115 kg pure N) in 2022. Subplots comprised four sesame varieties: Mohajer, Chamran, and Barkat (new shatter-resistant commercial cultivars), and the local Dezful genotype (control).
Results: Nitrogen regimes significantly influenced phenological and yield-related traits. Increasing nitrogen application extended the duration of growth stages in both years. The highest urea rates (200 kg ha⁻¹ in 2021 and 250 kg ha⁻¹ in 2022) delayed 100% flowering to 62.5 days (1460 GDD) and 65.7 days (1533 GDD), respectively. The local Dezful genotype required the most days to full flowering (66.4 days, 1540.3 GDD in 2021; 71.1 days, 1672.3 GDD in 2022), whereas shatter-resistant varieties showed minimal differences. Maximum grain yield occurred at the highest nitrogen rates. Mohajer outperformed other varieties, yielding 924 kg ha⁻¹ (2021) and 1953 kg ha⁻¹ (2022). NUE declined with higher nitrogen rates; Mohajer exhibited the highest two-year average NUE at 100 kg ha⁻¹ urea (16.9 kg grain per kg N) in 2021 and 150 kg ha⁻¹ (25.5 kg grain per kg N) in 2022. Barkat demonstrated high NUE in 2022 (20.4 kg grain per kg N), highlighting its efficient nitrogen utilization.
Conclusion: Overall, increased nitrogen application delayed sesame growth stages and prolonged vegetative phases. Advanced shatter-resistant varieties reached maturity faster than the control, requiring fewer days and growing degree days (GDD), reflecting earlier maturity. NUE decreased with higher nitrogen rates, and Mohajer and Barkat showed superior efficiency. Based on findings, 150 kg ha⁻¹ urea is recommended to optimize NUE in shatter-resistant cultivars.
Keywords: Early maturity, grain yield, growth stages, nitrogen use efficiency, phenology, shatter-resistant, urea
کلیدواژهها [English]
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