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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]

A two-year experiment (2017-2019) was conducted at Karaj, Iran, to investigate the effect of ammonium and potassium sulfates on the physiological traits and seed and oil yields 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 (full irrigation, restricted irrigation from flowering and siliqueformation stages) as the main plots and a combination of ammonium sulfate (0, 25, 50, and 75 kg ha-1) and potassium sulfate (0, 25, 50, and 75 kg ha-1) fertilizers as the subplots. Leaf relative water content, canopy temperature, stomata resistance, proline, carbohydrate, chlorophyll and seed and oil yields were affected by the three-way interaction between irrigation regime, ammonium and potassium sulfates. Camelina seed and oil yields were 2470 and 833 kg ha-1 in full irrigation, 613 and 118 kg ha-1 in restricted irrigation from the flowering stage, and 1320 and 407 kg ha-1 in restricted irrigation from the silique formation stages, respectively. Application of ammonium and potassium sulfates increased seed and oil yields in all irrigation treatments. The maximum seed and oil yields were obtained from 75 kg ha-1 ammonium + 75 kg ha-1 potassium sulfates with the averages of 1950 and 643 kg ha-1, respectively. The results of this study suggest that the application of 75 kg ha-1 ammonium + 75 kg ha-1 potassium sulfates can improve the camelina seed and oil yields under full irrigation and late-season drought stress treatments. [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]