Study of plant density and gibberellin on some morphological and physiological traits and essential oil content of coriander (Coriandrum sativum L.)

An experiment was conducted to evaluate the effects of plant densities (20, 30, 40, and 50 plants per square meter) and foliar application of gibberellin in two levels (0 and 100 Μg L-1) on some of the physiological and morphological traits of coriander (Coriandrum sativum L.). The experiment, carried out in the research farm of Bojnourd Payame Noor University in 2016, was based on a Randomized Complete Blocks (RCB) with three replications. The effects of 20-plant density with gibberellin spray showed the highest plant dry matter percentage as well as the highest number of lateral branches and leaves. The application of gibberellin increased the sugar content by 12.7% in comparison to the control sample; additionally, the highest sugar content (220.79 mg.g-1 F.W) was obtained in the 20-plant density. By increasing the plant density, the content of chlorophyll a, b, and carotenoids decreased. The interaction effect of the 20-plant density ×gibberellin with 72.11 mg.g-1 F.W caused the highest content of chlorophyll a, while the lowest content was recorded for the 50-plant density ×control with 60.7 mg.g-1F.W. The application of gibberellin caused superiority in both seed yield (686.22 Kg.ha-1) and essential oil (0.327%) compared to the control sample. The highest number of compound umbrella and the highest number of seeds per compound umbrella were obtained in the 20 and 30- plant densities, respectively. However, the 1000-seed weight, ultimate yield, oil yield, and essential oil percentage were the highest in the 50-plant density. In general, in higher densities, the ultimate yield seems to increase due to the increased number of plant per unit area, but the yield components are reduced.