S06 - Session O3 - Hemp varieties performance under supplementary lighting using LED and HID lamps in greenhouse cultivation.

Authors: Antonio Ferrante *, Giacomo Cocetta, Francesco Florio, Davide Guffanti, Gabriele Cola

Hemp ( Cannabis sativa L.) is a crop that belongs to the Cannabaceae family, is native to Central Asia, but now cultivated worldwide. Hemp was mainly grown to produce textile fiber. Moreover, the abundance of secondary metabolites, mainly psychotropic alkaloids, and terpenes, has promoted its use as drug since past times. there is a growing interest in this crop, supported by laws changes related to hemp-derived products, such as seed oil. Hemp seed contains 20-25% protein, 20-30% carbohydrates, 25-35% oil and 10-15% insoluble fiber and minerals. The oil is rich in highly polyunsaturated fatty acids and shows a 3:1 ratio of linoleic and linolenic acid. This feature, together with the presence of γ-linolenic acid, has also promoted its application in cosmetic. The aim of this work was the development of a greenhouse hemp cultivation system during the extra-seasonal period. Plants were grown under supplemental lighting by using HID and LED lamps for two seasons 2020 and 2021 from September-October to February-March. Six hemp varieties were tested: Carmagnola, Carmagnola Selezionata, Felina 32, Futura 75, Uso 31, and Santhica 27 aiming to identify the best performing genotypes. Plant growth rate, chlorophyll, flavonoids leaves content, and chlorophyl a fluorescence were measured. At the end of the growing cycle, the total biomass and seed yield were measured as well. Therefore, the seeds harvested were processed and a mechanical oil extraction was performed. The results show that plants grown under LED lamps have accumulated significantly higher biomass compared to the plants grown under HID lamps. The results are also supported by the higher seed yield obtained from the LED growing system. Chlorophyll a fluorescence parameters were higher in plants grown under LED light. Finally, the best results in terms of adaptation and eco-physiological responses were observed for the varieties Carmagnola, Carmagnola Selezionata, and Felina 32.