The effects of phosphite on strawberry yield and fruit quality

Phosphite (H2PO3-; Phi) has been shown to increase fruit quality and activate plant defense mechanisms in plants when provided in a nutrient state with sufficient phosphorous. In this study, five solutions containing different percentages of Phi (0, 20, 30, 40 and 50%) in Steiner's solution were evaluated during the flowering and fructification stages; the Steiner' s nutrient solution was kept al 50% during the flowering stage and at 75% from the beginning of the fructification stage on. The objective was to determine the effects of phosphite on total P concentration in leaves, yield, pH, electrical conductivity (EC), anthocyanin concentration, and fruit size of strawberries (cv. Festival). The experiments were performed in a tunnel-type greenhouse using drip irrigation and volcanic rock (volcanic gravel) as substrate. In the fruit development phase, the concentration of P in the leaves was proportional to the level of Phi used. Although no significant differences were observed when compared to the control, the addition of 20% Phi slightly improved yield and fruit size. The highest pH, EC and anthocyanin concentration were identified in the fruit of plants treated with 30% Phi. Our findings suggest that supplying Phi at 30% or less in the nutrient solution does not significantly affect yield but does affect fruit quality and activates plant defense mechanisms by producing a higher concentration of anthocyanins.