Abstract
This study was conducted to investigate the effect of changing the nutrient concentration at different plant growth stages on growth, yield, fruit quality and physiological characters of tomatoes (Lycopersicon esculentum Mill.) grown hydroponically. Nutrient concentrations adopted were ; a) 1.2 (L), b) 1.8 (M) and c) 3.0 mS/cm (H) . Growth stages when the treatments of nutrient concentration started were, a) florescence, b) fruit development and c) harvesting of the first truss respectively. Treatment combinations were ; LMH ; LMM ; MMM ; HMM ; and HHH. The results are as follows ; No significant difference was observed in the plant fresh weight among treatments. Higher rates of photosynthesis and respiration were recorded in the plants of lower nutrient concentrations. Low uptakes of water and Ca were observed in the plant of higher nutrient concentrations. The occurrence of blossom-end rot was the highest when nutrient concentrations were kept at high levels. Fruit sugar content and titratable acidity were relatively higher in the plants grown under higher nutrient concentrations. These results indicated that changing the nutrient concentration over a wide range affected clearer influences on yield, fruit quality and plant physiology, than those grown without changing the nutrient concentration in tomato plants grown hydroponically.
