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A two-year experiment was arranged as a factorial in a randomized complete block design with three replicates to investigate the response of camelina oil yield and its oil composition to irrigation regimes at different sowing dates in Karaj, Iran. The experiment factors were irrigation regimes including (i) full irrigation (well-watered), (ii) restricted irrigation from silicle formation (late-stress), (iii) restricted irrigation from flowering (mild-stress) and (IV) restricted irrigation from maximum stem length (early-stress) and planting dates consisting of (i) 27-Sep, (ii) 12-Oct and (iii) 25-Oct. The highest oil content (30.04%) was obtained from the first sowing date and was 2% and 5.4% higher than 12-Oct and 25-Oct, respectively. Obtained grains from well-watered irrigation regime had significantly more oil content (31.02%) than the other irrigation regimes. Delaying in sowing date and water-deficit stress raised saturated fatty acids (palmitic, stearic and arachidic acids). While delayed sowing date (12 and 25-Oct) and water-deficit stress (low, mild and severe stresses) increased the content of palmitic, eicosenoic and erucic fatty acids, the oleic, linoleic and linolenic acids were reduced in such conditions. It seems that postponing the sowing date to 12-Oct and restricting irrigation from silicle formation would be reasonable as it can decline water consumption. [ABSTRACT FROM AUTHOR]

To select and introduce the best rapeseed genotypes under withholding irrigation, two field experiments were carried out in seasons 2015–2016 and 2016–2017 in Iran. Factorial arrangement of treatments was set up as RCBD with three replications. The experiment factors were two irrigation treatments (normal irrigation during the growing season and withholding irrigation from silique setting stage until the end of the growing season) and 17 genotypes of rapeseed. Grain yield, oil content and fatty acid contents were measured. The results revealed that oleic acid (62.15%) was the highest followed by linoleic (19.28%), linolenic (5.65%), palmitic (5.24%) and stearic acids (2.44%). ODR (oleic desaturation ratio) and LDR (linoleic desaturation ratio) were significantly affected by genotypes and irrigation treatments. The biosynthetic pathway of fatty acids affected by drought stress. This means that linoleic acid increases under withholding irrigation condition, while linolenic acid decreases in such a water deficit stress condition. The highest performance of qualitative and quantitative was detected in HL3721 genotype due to high values of grain yield (3892.45 kg ha−1), oil content (437.05 g kg−1), unsaturated fatty acids (87.63%) and low values of saturated fatty acids (7.98%), and it could be used under withholding irrigation in arid and semi-arid climates. [ABSTRACT FROM AUTHOR]

• Camelina yield decreased by 46 % in restricted irrigation from pod formation stage. • Restricted irrigation from flowering stage caused reduction in seed yield by 51 %. • Camelina oil content significantly decreased when plants experienced drought. • Seed yield and oil content responded positively to potassium and ammonium sulfate fertilizer application. • Oil composition was affected by drought stress and potassium and ammonium sulfate fertilizer application. Camelina (Camelina sativa L. Crantz) is an oilseed crop belonging to the Brassicaceae family, which is a rich source of oil (28–40 %), as well as an excellent potential source of α-linolenic acid, a precursor for omega-3 fatty acid. A two-year experiment (2017-19) was conducted to investigate the effect of potassium sulfate and ammonium sulfate on several qualitative and quantitative traits of camelina under late-season deficit irrigation conditions. The experiment was carried out as a split plot-factorial in a randomized complete block design with three replicates and irrigation regimes (regular irrigation, restricted irrigation from flowering and pod formation stages) as the main plots and a combination of potassium sulfate (0, 25, 50, and 75 kg ha−1) and ammonium sulfate (0, 25, 50, and 75 kg ha−1) fertilizers as the subplots. The results showed that studied traits (seed yield, oil content and yield, oleic acid, linoleic acid, linolenic acid, eicosenoic acid, erucic acid, and glucosinolate substances) were affected by a three-way interaction between irrigation regime × potassium sulfate × ammonium sulfate. While the seed yield, oil content and yield, oleic, linoleic, and linolenic acid were significantly decreased when drought stress treatments were applied, the eicosenoic acid, erucic acid, and glucosinolate contents were increased in such conditions. On average, by irrigation regimes, an increase in the seed yield, oil content and yield, oleic, linoleic, and linolenic acid were observed when the camelina plants were treated with the ammonium sulfate and potassium sulfate fertilizers, while the eicosenoic acid, erucic acid, and glucosinolate contents were decreased. Generally, camelina should be cultivated in the full irrigation conditions and treated with the potassium sulfate (75 kg ha-1) + ammonium sulfate (75 kg ha-1) fertilizers for achieving the maximum seed and oil yields. [ABSTRACT FROM AUTHOR]