INFLUENCE DU NIVEAU D’IRRADIANCE D’APPOINT (HPS) EN PEPINIERE SUR LA CROISSANCE ET LA PRODUCTIVITE D’UNE CULTURE DE TOMATE DE SERRE.

Abstract

Tomato plants (Lycopersicon esculentum Mill. ’Vendor’) were seeded at three different dates between 23 Jan. and 17 Feb. 1984. Young tomato plants received the following supplementary lighting treatments: natural light only, and natural irradiance supplemented by 10, 20 or 30 W m−2 (PAR) for a photoperiod of 17 h. Twenty-nine days after the first seeding date, shoot dry weight of plants grown under 10, 20 or 30 W m−2 was, respectively, 311, 378 and 458% of the control. Shoot dry weight of the third seeding was 159, 181 and 207% of the control for the 10-, 20- or 30-W m−2 treatments, respectively. Early yields were increased by 19,4, 31,2 and 42% when tomato transplants received 10, 20 or 30 W m−2. Total yields were not significantly affected by supplementary lighting provided in the nursery period.Key words: Tomato, supplementary light, growth, productivity, HPS, Lycopersicon esculentum Mill.