Electrical Conductivity Effects on Physico-chemical Characteristics and Vitamin C Content of the Fruits of Solanum lycopersicum var. cerasiforme Hybrids Grown in Hydroponics System
Paul Christian T. Gloria1 , Primitivo Jose A. Santos2 , Charles Anthon E. Cadorna1 , Ronaldo B. Saludes3 , Arthur R. Baria4 , Carlos Primo David5 , and Jessica D. Rey1*
1 Institute of Biology, College of Science, University of the Philippines (UP) Diliman, Quezon City, Philippines; 2 Institute of Plant Breeding, College of Agriculture and Food Science, University of the Philippines Los Baños (UPLB), Laguna, Philippines; 3 Institute of Agricultural and Biosystems Engineering, College of Engineering and Agro-Industrial Technology, UPLB, Laguna, Philippines; 4UP Mindanao, Tugbok, Davao City, 8000 Davao del Sur, Philippines; 5National Institute of Geological Sciences, College of Science, UP Diliman, Quezon City, Philippines. *Corresponding author, jdrey@up.edu.ph


Solanum lycopersicum var. cerasiforme (tomato) is an economically important commodity in the Philippine fresh vegetable market and is also considered as a model system for fruit development studies. This study was conducted to establish baseline data on the effect of electrical conductivity (EC) on the physical, biochemical, and nutritional quality of the fruits at different developmental stages using two cherry tomato hybrids, namely Sweet Princess (SP) and Cutie Pie (CP), grown in Simple Nutrient Addition Program (SNAP) hydroponics system. A replicated experiment with three EC treatments using NaCl (1.2 dS m-1, 1.5 dS m-1 , and 2.0 dS m-1) was established while total soluble solids (TSS), vitamin C content, titratable acidity (TA), yield or weight of the fruits were measured at different fruit development stages namely, green, turner and red. Results showed that EC of nutrient solution affected the total soluble solids, vitamin C content, and titratable acidity of two cherry tomato hybrids, SP and CP. Our study establishes the significant effect of EC 1.5 on TSS, which is increased at turner stage, on TA and Vitamin C at red stage for SP and subsequent decrease in fruit weight and TA, while that of CP hybrid, EC 1.5 significantly decreases TSS, TA and fruit weight, but increases Vitamin C content at turner stage. EC 2.0 has significant increase on TSS, TA and fruit weight of SP hybrid only. These results are initial reports for the Philippine cherry tomato hybrids grown in hydroponics system. Further studies with larger population size to further minimize the variations between replication and to conduct more technical replications in the assays is recommended.

Keywords: electrical conductivity (EC), SNAP nutrient solution, hydroponics, cherry tomato