Univrsity of Tehran Press Iranian Journal of Field Crop Science 2008-4811 53 1 2022 03 21 Effects of nitrogen rate and supplemental irrigation time on yield and agro-morphological traits of spring wheat Effects of nitrogen rate and supplemental irrigation time on yield and agro-morphological traits of spring wheat 175 188 87864 10.22059/ijfcs.2021.318392.654800 FA Hossein Vaziri Department of Agronomy, Gorgan Branch, Islamic Azad University, Gorgan, Iran Mohammad Reza Dadashi Department of Agronomy, Gorgan Branch, Islamic Azad University, Gorgan, Iran Hossein AjamNorozi Department of Agronomy, Gorgan Branch, Islamic Azad University, Gorgan, Iran Afshin Soltani Faculty of Plant Production, Gorgan University of Agriculture and Natural Resources, Gorgan, Iran Saeed Yarahmadi Horticulture-Crops Research Department, Golestan Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Gorgan, Iran Journal Article 2021 02 07 In order to investigate the effects of nitrogen rate and time of irrigation on the grain yield and yield components of wheat, an experimental was conducted as split plot based on randomized complete block design with four replications in the research farm of Aliabad Katoul Emam Khomeini agriculture high school during 2018-2019 and 2019-2020. Irrigation time was in the main plots (no irrigation and irrigation at 33and 70 zadoks stages) and nitrogen rate was in the sub plot (zero, 57.5 and 115 kg N/ha from urea source). Significant interaction was not observed between irrigation treatments and nitrogen rates in almost all traits. The highest yield was obtained using a supplementary irrigation in 70 Zadox stage and 115 kg of pure nitrogen treatments. Grain yield had a positive correlation with biological yield, spike length snd weight, number of seeds per spike and seed weight per spike. Factor analysis revealed that the first two factors explained 74.5% of the total variation. The results of stepwise regression analysis showed that only the spike weight entered the model and justified 80.7% of the grain yield variation alone. In order to investigate the effects of nitrogen rate and time of irrigation on the grain yield and yield components of wheat, an experimental was conducted as split plot based on randomized complete block design with four replications in the research farm of Aliabad Katoul Emam Khomeini agriculture high school during 2018-2019 and 2019-2020. Irrigation time was in the main plots (no irrigation and irrigation at 33and 70 zadoks stages) and nitrogen rate was in the sub plot (zero, 57.5 and 115 kg N/ha from urea source). Significant interaction was not observed between irrigation treatments and nitrogen rates in almost all traits. The highest yield was obtained using a supplementary irrigation in 70 Zadox stage and 115 kg of pure nitrogen treatments. Grain yield had a positive correlation with biological yield, spike length snd weight, number of seeds per spike and seed weight per spike. Factor analysis revealed that the first two factors explained 74.5% of the total variation. The results of stepwise regression analysis showed that only the spike weight entered the model and justified 80.7% of the grain yield variation alone. https://ijfcs.ut.ac.ir/article_87864_e364236bcb7c81cc145c1e649b828f74.pdf