Stimuli Effects of Different LEDs on Some Morphological and Biochemical Traits of Two Varieties of Calendula officinalis

In the production of flowers and ornamental plants, especially in the advanced greenhouse conditions, it is important to have a good light source and its accurate management. This study aimed to evaluate the effect of light quality on morphological and biochemical traits of two Marigold genotypes (Iranian-native and Gitana). This experiment was conducted in a completely randomized design with three replications. The treatments included five light qualities including red, blue, 70% red:30% blue (70%:30%), and white lights with an intensity of 500 μmol m-2 s-1 [photosynthetic photon flux density (PPFD)] and greenhouse natural light (with an average intensity of 650 PPFD). The results showed that light quality had significant effects on all studied traits at p<0.01. Genotypes had significant effects on the dry weight of the aerial parts, the number of open flower, and chlorophyll b concentration. The interaction effect of light and genotype was significant on the fresh and dry weight of the aerial parts. Between the two genotypes, the Gitana was significantly superior to Iranian-native genotype for the content of chl b. Among the light qualities, the highest number of flowers per plant, chlorophyll b and carotenoid concentrations were observed in plants that exposed to red light. Increase in all studied traits especially in plant height, total flavonoids and chlorophyll a, b, total, and carotenoid concentrations were observed in the plants that exposed to red, blue, and red/blue lights. In conclusion, growing both Marigold genotypes under red, blue and composition of red/blue light, improves quality and quantity of production of Marigold flower in the greenhouse condition.