University of Tabriz Journal of Agricultural Science and Sustainable Production 2476-4310 33 2 2023 06 22 Investigation of the effects of drought stress and nitrogen fertilizer on yield, yield components and some physiological characteristics of wheat Investigation of the effects of drought stress and nitrogen fertilizer on yield, yield components and some physiological characteristics of wheat 49 60 16605 10.22034/saps.2021.44393.2630 FA Mehrdad Mahlooji Assistant Professor, Horticulture Crops Research Department, Isfahan Agricultural and Natural Resources Research and Education Center, AREEO, Isfahan, Iran Siavash Bardehji 2. Department of Agronomy and Plant Breeding, Faculty of Agricultural and Natural Resources, Isfahan University of Technology, Isfahan, Iran Saeid Omrani 2. Department of Agronomy and Plant Breeding, Faculty of Agricultural and Natural Resources, Isfahan University of Technology, Isfahan, Iran Journal Article 2021 02 05 Background and Objective: This experiment was performed to investigate the effects of drought stress and nitrogen fertilizer on yield, yield components and some physiological characteristics of four wheat cultivars.<br />Materials and Methods: The experiment was carried out in double split plots in a randomized complete block design with three replications in the research farm of Isfahan University of Technology. Experimental factors include two irrigation regimes (irrigation 100 and 50% of plant water requirement for normal and drought stress, respectively), two levels of nitrogen fertilizer (soil content and use of 150 kg urea per hectare) and wheat cultivars (Pishtaz, Bahar, Sepahan and Star). <br />Results: Drought stress decreased grain and biomass yield by decreasing the content of chlorophyll a, b, carotenoids and leaf relative water content as well as increasing the amount of ion leakage. The use of nitrogen under normal irrigation conditions increased grain and biomass yield, but under drought stress conditions increased biomass and decreased grain yield. Pishtaz cultivar had the highest grain yield (4710 kg / ha), and Star cultivar had the highest amount of biomass (11639 kg / ha). Also, the highest grain and biomass yield were observed in normal irrigation and nitrogen treatment. <br />Conclusion: The use of nitrogen to increase yield depends on the amount of water available to the plant, and under drought stress conditions, the use of nitrogen is not only a good way to reduce the impact of water stress and yield, but also intensify stress and reduce grain yield of studied wheat cultivars. Background and Objective: This experiment was performed to investigate the effects of drought stress and nitrogen fertilizer on yield, yield components and some physiological characteristics of four wheat cultivars.<br />Materials and Methods: The experiment was carried out in double split plots in a randomized complete block design with three replications in the research farm of Isfahan University of Technology. Experimental factors include two irrigation regimes (irrigation 100 and 50% of plant water requirement for normal and drought stress, respectively), two levels of nitrogen fertilizer (soil content and use of 150 kg urea per hectare) and wheat cultivars (Pishtaz, Bahar, Sepahan and Star). <br />Results: Drought stress decreased grain and biomass yield by decreasing the content of chlorophyll a, b, carotenoids and leaf relative water content as well as increasing the amount of ion leakage. The use of nitrogen under normal irrigation conditions increased grain and biomass yield, but under drought stress conditions increased biomass and decreased grain yield. Pishtaz cultivar had the highest grain yield (4710 kg / ha), and Star cultivar had the highest amount of biomass (11639 kg / ha). Also, the highest grain and biomass yield were observed in normal irrigation and nitrogen treatment. <br />Conclusion: The use of nitrogen to increase yield depends on the amount of water available to the plant, and under drought stress conditions, the use of nitrogen is not only a good way to reduce the impact of water stress and yield, but also intensify stress and reduce grain yield of studied wheat cultivars. https://sustainagriculture.tabrizu.ac.ir/article_16605_8fd78994ea95f3ea49a7722cfe1fcd66.pdf