S01 - Session O9 - II - Lettuce cultivated in a nutrient film technique (NFT) hydroponic system display variable tocopherol and phylloquinone content

Authors: German Sandoya-Miranda *, Gilles Basset, Robert Hochmuth , Wanda Laughlin

Lettuce ( Lactuca sativa L.) is the most cultivated crop in protected horticulture, including hydroponics, aquaponics and vertical towers, and is among the top ten most consumed vegetables in the United States. Here, 43% of the area dedicated to food crops grown under glass and other protections is used to produce vegetables and fresh cut herbs, including lettuce. Lettuce contains many minerals and vitamins including alpha- and gamma-tocopherols (Vitamin E) and phylloquinone s (Vitamin K 1 ), both of which are vital to humans. The objective of this research was to screen lettuce in a hydroponic system for horticultural traits, and tocopherols and phylloquinone levels. Three experiments were conducted in a greenhouse using a nutrient film technique (NFT) hydroponic system with 30 lettuce cultivars and breeding lines of four different lettuce types (romaine, Boston, Latin and leaf). The recorded horticultural traits were head weight (HW), marketability, and head height and width. Three lettuce disorders were also registered: tipburn, chlorosis and bolting. High yielding (expressed as HW and related traits including height and width) cultivars with good marketability were found within each type, while cultivars with less tipburn, chlorosis and bolting were also registered. Romaine and Latin lettuce had the highest content of alpha-tocopherol, while leaf lettuce had the highest content of gamma-tocopherol. Romaine, Boston and leaf lettuce had the highest level of phylloquinone. A significant cultivar × experiment interaction was detected for tocopherols, phylloquinone, HW and its related traits, indicating that this phenomenon should be taken into consideration while breeding lettuce for higher content of these compounds. Lettuce accessions identified in this research can serve as a source of breeding for vitamins and performance in the NFT system.