Tomato quality and mineral content dependent on cultivar and nutrient solution composition

Vegetables are the most important source of vitamins, minerals and bioactive compounds to humans. Since the change of nutrient solution composition and electrical conductivity could affect to the quality improvement, the aim of this study was to determine the qualitative properties and mineral content of four tomato cultivars grown at different calcium nitrate concentrations in the nutrient solution. The concentration of calcium nitrate ranged from 0.425 to 1.70 mmol L-1, and the variation began a month after planting. Qualitative traits (dry matter and soluble solids content, pH, total acidity and ascorbic acid content) and mineral content (total nitrogen, phosphorus, and potassium) were determined periodically, three times during the harvest period. Samples for analysis were consisted from six fruits with uniform size and maturity. Depending on the cultivar and the calcium nitrate concentration, dry matter content varied from 4.74 to 6.27%, while the soluble solids content was between 4.08 and 5.18 °Brix. During the harvest period pH-value of fruits was decreasing while total acidity was increasing in all cultivars. Differences in the amount of vitamin C among the tested cultivars (from 12.41 to 22.95 mg per 100 g fresh weight) were determined. Depending on the applied solution, vitamin C content ranged from 12.68 to 22.69 mg per 100 g fresh weight. The cultivars were different in the macroelements content. The lowest nitrogen (2.163 and 2.379% dry matter) was found in fruits harvested from plants fertigated with lower calcium nitrate concentration, while higher amounts were determined when higher calcium nitrate concentrations than standard were applied. A similar trend was found for phosphorus and potassium. Cultivars ‘Fado’ and ‘Rally’ had the highest dry matter and soluble solids content, and the amount of vitamin C. The highest phosphorus and potassium content was determined in ‘Rally’ and ‘Mondial’ fruits.