Growth, yield and antioxidant capacity of strawberry under various K+:Ca++ ratios in hydroponic culture

Optimisation of the mineral composition of the nutrient solution is one of the most important factors affecting crop productivity and quality under hydroponic cultivation. Considering the role of minerals in nutrition and the lack of studies on the K+:Ca++ ratio of nutrient solution on fruit quality, a study was carried out to evaluate the effects of K+:Ca++ ratios on growth, yield, vitamin C content of the fruit and total carbohydrate and phenolic compounds of the ‘Paros’ strawberry under hydroponic conditions. The highest total phenolic compounds, photosynthetic capacity, including leaf area, photosynthetic pigments, stomatal conductance and yield were observed at the 1.4 ratio (K > Ca). Enzymatic (peroxidase, superoxide dismutase and catalase) and non-enzymatic (total phenol, phenolic compounds and anthocyanin) antioxidant capacities were affected significantly by the K+:Ca++ ratio. The highest antioxidant capacity was observed in ratios with K > Ca in the solution. We recommend growers to maintain an appropriate K+:Ca++ ratio in the nutrient solution, as this affects growth parameters, productivity and strawberry quality.