Optimizing Chia (Salvia hispanica L.) Cultivation in Iran Regions: A Study on Planting Density and Growth Regulator Effects

Chia (Salvia hispanica L.) is an annual plant of the Lamiaceae family that has commercial value due to its omega-3 and omega-6 content. Considering the limited cultivation of this plant in Iran, the effect of planting density and growth regulators under Gorgan weather conditions was investigated in this research. This research was conducted as a factorial design based on a randomized complete block design with 3 replications. The treatments included the cultivation distance (50, 60, and 70 cm), growth regulators including ethephon (0, 10, 30, and 60 mg), and daminozide (0, 25, 75, and 150 mg). The measured variables include morphological and yield traits (wet weight and dry weight of leaves, plant height, number of side branches, stem diameter, leaf area, number of inflorescences per plant) and phytochemical traits (total phenol, total flavonoid, mucilage, antioxidant activity by three methods (DPPH, TAOC, and FRAP)). Results indicate significant effects of ethephon and daminozide on plant growth, with differential impacts on morphological traits and reproductive growth. Specific combinations of ethephon and daminozide treatments influenced phytochemical composition, with notable variations in total phenol and flavonoid content. Antioxidant activity varied across treatments and assays, suggesting complex interactions between growth regulators and antioxidant metabolism. Additionally, mucilage production responded to growth regulator applications, with specific combinations yielding the highest mucilage content, notably with 30 ppm ethephon and 25 ppm daminozide at 70 cm row spacing. These findings contribute to optimizing chia cultivation practices and harnessing its potential as a functional food source with diverse health benefits.