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Evaluation of nitrogen fertilizer application on dry matter accumulation, partitioning and remobilization in two sunflower hybrids
(Helianthus annuus L.)
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Behrouz Farrokhi   , Ebrahim Khalilvand Behrouzyar * , Bahram Mirshekari , Mehrdad Yarnia , Varahram Rashidi |
| Department of Agronomy, Ta.C., Islamic Azad University, Tabriz, Iran. |
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Abstract: (11 Views) |
To evaluate of nitrogen fertilizer application on dry matter accumulation, partitioning and remobilization in two sunflower (Helianthus annuus L.) hybrids, a split-plot experiment based on a randomized complete block design with three replications was conducted over two growing seasons (2024–2025) in a field located in Qaleh village, Soltaniyeh County, Zanjan Province. The experimental factors consisted of: two sunflower single-cross hybrids at two levels (Shams and Ghasem) in main plots and five levels of nitrogen fertilizer (control, and 40, 80, 120, and 160 kg/ha of pure nitrogen from urea source) in sub plots. Based on the analysis of variance results, the three-way interaction (year × fertilizer × cultivar) were significant for dry weights of leaves and vegetative organ at anthesis; the interaction (year × block) for dry weights of stem, head and vegetative organ at maturity as well as for the remobilization of storage material and remobilization efficiency; the interaction (year × fertilizer) for stem dry weight and remobilization of storage material; the interaction (fertilizer × cultivar) for dry weight of vegetative organ at maturity, remobilization of storage material, remobilization efficiency, remobilization contribution, sunflower grain yield. A comparison of the mean data across the two cropping seasons revealed that treatments Shams hybrid + 160 kg/ha nitrogen fertilizer and Ghasem hybrid + 160 kg/ha nitrogen fertilizer yielded the highest averages 5.201 and 3.852 kg/ha and treatments Shams hybrid + without fertilizer and Ghasem hybrid + without fertilizer produced the lowest grain yields 3.347 and 2.839 kg/ha representing increases of 55.4% and 35.68%, respectively. The highest mean rates of remobilization of storage material were observed in treatments Shams hybrid + without fertilizer and Ghasem hybrid + without fertilizer at 753.8 and 684.5 kg/ha and the lowest mean rates were found in treatments Shams hybrid + 160 kg/ha nitrogen fertilizer and Ghasem hybrid + 160 kg/ha nitrogen fertilizer at 524.3 and 504.2 kg/ha representing increases of 43.77% and 35.76%, respectively. In this study, across both cropping seasons, grain yield and the dry weight of sunflower plant parts increased progressively with rising nitrogen application; this increase was significant for the Shams hybrid compared to the Ghasem hybrid. In contrast, remobilization of storage material and remobilization efficiency in the sunflower gradually declined; this reduction was more pronounced in the Ghasem hybrid compared to the Shams hybrid. With increased nitrogen application, a greater supply of assimilates becomes available for grain yield production and the remobilization of storage material decreases.
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| Keywords: Dry matter remobilization, nitrogen levels, grain yield, and sunflower. |
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Full-Text [PDF 876 kb]
(8 Downloads)
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Type of Study: Research |
Subject:
Crop Physiology
Received: 2026/07/19 | Accepted: 2026/05/31 | Published: 2026/05/31
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