Abstract

SAN MARTIN-HERNANDEZ, Cesar et al. Tomato (Solanum lycopersicum L.) quality produced in hydroponics with different particle sizes of tezontle. Agrociencia [online]. 2012, vol.46, n.3, pp.243-254. ISSN 2521-9766.

The quality of the tomato fruit (Solanum lycopersicum L.) is affected by genotypic variation, climatic conditions, and the production system used. The objective of this study was to evaluate the physical and chemical quality of the tomato fruit produced in hydroponics and tezontle (cooled molten rock in volcanic vent) used as substrate in four particle sizes: 3-5, 5-10, 10-20 and 20-30 mm in diameter (treatments T1, T2, T3 and T4); mixed with coconut dust and fiber (CDF) in a 3:1 proportion. Plastic containers were used with 24 L of substrate in which three tomato seedlings were transplanted. During the growing season from October 2009 to April 2010, the plants were drip-irrigated daily. Electrical conductivity (EC) and pH of the nutrient solution in contact with the root were monitored monthly. The experimental design was completely randomized, with three containers per experimental plot and five replicates per treatment. Mature fruits were used in the analysis of: total soluble solids (TSS), titratable acidity (TA), TSS/ TA ratio, EC, pH, juice percentage, firmness and color (lightness, hue and chroma). We conducted an analysis of variance and applied the HSD Tukey test (p≤0.05) to compare the treatment means. The results showed that the particle size of tezontle mixed with CDF (3:1) did not affect (p>0.05) SST, AT, SST/AT ratio, EC, and chroma of the fruit, but there were differences (p≤0.05) in the pH and the juice percentage, brightness, hue and the fruit firmness. By water supply, easily available, salinity and alkalinity were generated in the substrate, which in addition to temperature influenced the physicochemical quality attributes of the tomato fruit.

Keywords : Solanum lycopersicum L.; quality attributes; substrate granulometry; salinity; hydroponics.