The effect of nitrate: Ammonium ratios on fruit quality of the strawberry cultivar 'Selva'

Strawberry plants (Fragaria x ananassa Duch. 'Selva') were grown for two successive growing seasons in a greenhouse in a mixture of 30% peat moss and 70% perlite at the University of Tehran, Faculty of Agriculture. They were fertigated daily in a non-recirculating drip irrigation system with complete nutrient solutions to determine the effect of four different nitrate: ammonium ratios (6:0, 6:0.5, 6:1, 6:1.5 mM) on some fruit quality characteristics. The quality parameters investigated were fruit firmness, titratable acidity, pH, color and vitamin C and soluble solids content. Fruit was picked and assessed at a specified ripening stage i.e. at 28 days after fruit set, which is the best stage for determining quality characteristics for consumption. Different nitrate: ammonium ratios had different effects on fruit quality parameters assessed in this experiment.