EFFECTS OF ENVIRONMENT ON TOMATO (Lycopersicon esculentum) FLOWERING AND FRUIT PRODUCTION

Abstract

An experiment was conducted under glasshouse conditions. Tomato plants cv. ‘Solarset’ where grown to evaluate the effects of low night air temperature (10 ºC) for 10 days, supplemenatry light (75 µmol^.m^-2.s^-1 with fluorescent lamps or 90 µmol^.m^-2.s^-1 with fluorescent + incandescent lamps) for five hours every nigth during 10 days and prunning of the fifth leaf. These treatments where applied to nursery plantlets during the initiation of the first inflorescence, and its effects were evaluated on the number of flowers formed per inflorescence (NFI), percentage of plants with their first inflorescence branched (PBI), yield and primary yield components. A subsplit plot design arranged in randomized blocks with four replications was used. There were not significant differences among treatments for the studied variables; however a high NFI (6.75) and PBI (30 %) were observed as compared to former results, indicating that nursery environment was fully adequate for inflorescence initiation of plants (including control plants). Leaves treated with supplementary light made additional photosynthesis at night, which was enough to compensate for the CO₂ lost by leaves respiration at night; however, the photosynthesis rate during the day tended to be higher in the leaves of plants without supplementary light, so that the net amount of photoassimilates produced per day was similar to that of plants treated with supplementary light.