ISHS Acta Horticulturae 580: IV International ISHS Symposium on Artificial Lighting
EFFECT OF DIFFERENT EC MANAGEMENT ON YIELD, QUALITY AND NUTRACEUTICAL PROPERTIES OF TOMATO GROWN UNDER SUPPLEMENTAL LIGHTING |
| Authors: | Z.-Q. Shi, F. Jobin-Lawler, A. Gosselin, G. Turcotte, A.P. Papadopoulos, M. Dorais |
| Keywords: | antioxidant, carotenoid, electrical conductivity, fertigation, flavonoid, Lycopersicon esculentum, russeting, salinity, vitamins |
| Abstract:
The yield, quality and nutraceutical properties of greenhouse tomato grown under supplemental lighting and using three different electrical conductivity (EC) management strategies were determined. The three EC management treatments were: 1) control EC; 1.8 to 3.5 mS cm-1 according to the solar radiation, 2) NaCl EC; EC equal to the control where macronutrients were used to obtain 1.8 mS cm-1 and NaCl was added to raise the EC to the control level, and 3) variable EC; low EC (1.5 to 2.7 mS cm-1) during the active growth period of the day (10-14 h) and high EC (3 to 4 mS cm-1) for the remaining part of the day. Tomato fruit was harvested 2 to 3 times per week from March to the end of June 2000 and fruit quality was graded into 4 categories according to the incidence of physiological disorders. The total yield, percentages of grade 1, 2 and 3 fruits were not significantly affected by EC management treatments, but the incidence of blossom-end rot (P=0.0003) and the percentage of grade 4 fruits (P=0.01) were significantly reduced by NaCl and variable EC treatments. NaCl did not affect the nutraceutical properties of tomato fruit such as antioxidant vitamins (ascorbic acid,  -tocopherol), carotenoids (lycopene,  -carotene, and lutein), and flavonoids (quercetin). However, variable EC resulted in an increase of -tocopherol and lycopene concentrations and a decrease of ascorbic acid and -carotene concentrations.
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