EFFECTS OF ADDITIONAL CALCIUM-GLUCONATE CONCENTRATIONS ON GROWTH AND FRUIT QUALITY IN HYDROPONIC TOMATO

The objective of this experiment was to increase fruit calcium in tomatoes produced by hydroponics in order to supply calcium more easily in calcium lacking groups such as higher aged, young children and pregnant women. This experiment was carried out to investigate the effects of additional calcium gluconate (Ca-glu) concentrations on growth and fruit quality of hydroponic tomato (Lycopersicon esculentum). Additional Ca-glu concentrations in Yamazaki’s tomato solution were 0 (control), 0.3, 0.6, and 0.9 me•L^-1, respectively. The standard solution composition of N-P-K-Mg-S was 7–2–4–3–2 (mg•L^-1), respectively. “Super momotaro” were planted on April 15 in 2005. Additional Ca-glu was supplied from planting to harvest time. Additional Ca-glu concentrations in solution did not affect plant height. The soluble solids content was not different among the treatments, but glucose was increased in 0.9 me•L^-1 Ca-glu treatment. There were irregular trends in fruit firmness and soluble solids. Total fruit weight and average fruit weight were decreased with high Ca-glu treatments. Cation concentrations of Ca, K, Mg, and Na in fruit were increased with addition of Ca-glu treatments. The high lycopene content was 0.6 me•L^-1 in the Ca-glu treatment.