Dragonhead is an annual species whose essential oil and extracts are widely used in the medicinal, food, cosmetic, and health industries. To evaluate the quantity and quality of dragonhead production under different sowing density patterns and nano-iron fertilization, a field experiment was perfumed. The measured traits were the number of flowering branches, height of first flowering branch, number of secondary branches, stem diameter, essential oil content, dry mass, essential oil yield, total anthocyanins, chlorophyll a, chlorophyll b, flavonoid 270 nm, flavonoid 300 nm, and total flavonoid. Results showed that the treatment × trait biplot accounted 39 % and 25 % respectively of total variation. The vertex treatments in polygon biplot were 5 cm density and 1 g l-1 nano-fertilizer) was the best in the essential oil content, dry mass and essential oil yield, while D4-N3 (40 cm density and 2 g l-1 nano-fertilizer) was the best for total anthocyanins, flavonoid 270 nm, flavonoid 300 nm and total flavonoid. According to the ideal treatment, all sowing densities with iron nano-fertilizer treatments (1 and 2 g l-1) were the best treatment for the measured traits of the dragonhead. Overall, the findings of the present study indicated that dragonhead cultivated under all sowing densities and fertilized with iron nano-fertilizer could improve the quality and quantity of dragonhead and can be suggested as special treatments for industrial production.
