Omega-3 in Dragon's head (Lallemantia iberica (MB) Fischer & Meyer) as effected by irrigation regimes and sowing date

In order to evaluate the effect of irrigation regimes and sowing dates on linolenic acid (Omega-3) content in dragon's head (Lallemantia iberica), an experiment was conducted factorial as a randomized complete block design in three replications in the research farm of Shahed University on crop year 2021–2022 in the research farm of Shahed University. The experimental treatments included: Irrigation regimes at three levels: I20: Irrigation after 20% depletion of soil available water (SAW); I40: An irrigation after 40% depletion of SAW; and IS20: Irrigation at sowing and before flowering based on 20% depletion of SAW. The second factor was the sowing dates of autumn (November 15) and spring (March 15). The interaction effect of autumn sowing date and irrigation regime I20 produced the greatest seed yield (680.1 kg.ha-1), harvest index (0.28), chlorophyll b content (0.457 mg.g-1 Fw), seed number per plant (469.0), and branch number per plant (9.83). Also, the amount of linolenic acid was greater under the treatment of sowing date and irrigation regime I20, with values of 64.07% and 64.33%, respectively. A water shortage in the soil also decreased linolenic acid content under deficit irrigation treatments (IS20 and I40) although in I40 it was not statistically different from I20. Totally, it was clearly determined that the low temperature of autumn increased Omega-3 in the Dragon's head.