کیمیا مومنی شیجانی

Oilseeds are rich in fatty acids, hence they are of paramount importance. Fats and oils are recognized as primary sources of energy in human nutrition. Additionally, fat-soluble vitamins, which play a crucial role in maintaining human health, are supplied through the consumption of oilseeds in the body. Therefore, studying and researching oilseeds and their importance in today's nutrition is crucial. Camelina is an oilseed product belonging to the Brassicaceae family, which can adapt well to various environments and produce suitable oil for biological purposes. Due to its appropriate composition of unsaturated fatty acids such as oleic acid (omega-9), linoleic acid (omega-6), alpha-linolenic acid (omega-3), and low levels of saturated fatty acids, it is considered one of the highest quality edible oils.

 This research aimed to investigate the performance and composition of camelina oil under the influence of urea foliar application and irrigation regimes in a split plot arrangement in randomized complete block design with three replications during 2021 growing season at the research farm of the Faculty of Agriculture, Tarbiat Modares University. In this study, the examined factors included different irrigation regimes at the flowering stage at four levels defined as the main factor. These levels included optimal irrigation (no stress), mild water deficit stress, moderate water deficit stress, and severe water deficit stress. Irrigation continued until the plant's available moisture in the root zone reached 20, 40, 60, and 80 percent, respectively, and then irrigation continued to the field capacity. The secondary factor included the application of nitrogen fertilizer from urea source as foliar spray at six levels (0% (distilled water spray), 1%, 2%, 3%, 4%, and no foliar spray (control)).

Under optimal irrigation conditions, seed yield and oil content showed the highest values, with the optimal irrigation treatment exhibiting the highest yield. In mild water deficit stress conditions, seed yield decreased by 12.83% compared to the control (optimal irrigation), while foliar application of nitrogen at concentrations of 1%, 2%, 3%, and 4% increased seed yield by 18.23%, 27.95%, 16.30%, and 11.74%, respectively, compared to the control (no foliar spray). In mild water deficit stress conditions, the use of nitrogen foliar spray at a concentration of 3% resulted in a greater increase in grain yield and oil content compared to other concentrations. Oil yield decreased by 4.42% and 21.23% in mild and moderate water deficit stress conditions, respectively, compared to the control (optimal irrigation). Additionally, foliar application of urea at concentrations of 1%, 2%, and 3% increased oil yield by 23.85%, 35.37%, and 23.81%, respectively, compared to the control (no foliar spray). Under severe water deficit stress conditions, the treatment with 2% nitrogen concentration led to the highest amount of seed oil, chlorophyll a, and chlorophyll b. Regarding the anthocyanin content, under severe water deficit stress conditions, foliar application of nitrogen at a concentration of 1% resulted in a greater increase in anthocyanin content compared to other treatments.

In optimal irrigation conditions, grain yield and oil content showed the highest values. In mild water deficit stress conditions, the use of foliar spraying of urea fertilizer with a concentration of 3% nitrogen led to a greater increase in grain yield and oil content than other concentrations. In severe water deficit stress conditions, urea fertilizer treatment with 2% nitrogen concentration resulted in the highest amount of  oil content and chlorophyll a and b.