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Asian Journal of Agriculture and Development (AJAD) - Call for papers!

Supplementary light for wet-season production of lettuce (Lactuca sativa Linn.) under protective cultivation

(Philippines), Master of Science in Horticulture (University of the Philippines Los Baños)

Thesis Abstract:

Romaine lettuce (Lactuca sativa L. cv. Romaine) was grown in containers under portable quonset protective structures from July 29 to August 20, 2010, coinciding with the wet season period in the Philippines. Supplementary light using warm white (emitted a red-yellowish tone mostly in the 600–650 nm region), cool white (emitted a bluish tone in the 400–450 nm region), and a combination of warm white and cool white compact fluorescent lamps (CFLs) were used to investigate the effects of light quality on plant growth, biomass accumulation, chlorophyll and carotenoid concentration, and marketable yield. Each treatment was further subjected to three light duration—three, six, and 12 hours. There was a significant effect of treatment using warm white CFL on fresh and oven dry weights. This was consequently translated into a significantly high marketable yield. Carotenoid concentration also increased with the use of supplementary light as compared to the control but not the chlorophyll level. Furthermore, plants exposed to longer supplementary light duration showed better development and amount of carbon fixed compared to those that received shorter duration or none at all. Results of the experiment showed that supplementary lighting satisfactorily compensated the limited solar radiation during the wet season production of lettuce under protective cultivation.