Effect of potassium and calcium foliar application on quantity and quality of strawberry (ragaria x ananassa Duch cv. Selva)

This experiment was conducted to evaluate the effects of foliar application of different K:Ca ratios (0, 0.5, 1 and 1.5) on growth parameters, yield and fruit quality of strawberry 'Selva' in greenhouse conditions based on completely randomized design with three replicates. Based on the results, spray application showed significant effects on the photosynthetic capacity, enzymatic and non-enzymatic anti-oxidant capacity and fruit yield. Accordingly, the maximum yield (92.6 g/plant) and photosynthetic capacity including leaf area (2060 cm2/plant), stomatal conductance (405.7 mmol (H2o)/m2.s-1) and chlorophyll content (18.04 µg/g Fw) were obtained in 1.5 ratio in compared to 0.5 and 1 ratios. Also, the highest enzymatic (peroxidase and catalase) and non-enzymatic (total phenol and vitamin C content) anti-oxidant capacity and total soluble solid were observed in 1.5 ratio; while the lowest fruit weight loss was observed in the ratio contains more Ca. The results of this experiment led to conclusion that foliar application of K:Ca treatments has significant effects on growth parameters and fruit quality components as well; consequently optimum ratio of K:Ca was the best treatment. Additionally, supplemental application of optimum K:Ca ratio especially under low nutrient uptake via substrate and also at different growth stages, could be recommended.