RESPONSE OF STRAWBERRY CV. FESTIVAL TO SALINITY

Abstract

Strawberry (Fragaria × ananassa Duch.) is a crop of socioeconomic importance for Mexico, its fruits have high nutritional value for humans; however, the effect of salinity on commercial cultivars is unknown; for this reason, the objective of this study was to determine the effect of salinity of the nutrient solution on growth, nutrient status, proline content, yield and quality of strawberry fruits cv. Festival. Plants were established in 1.8 L post capacity filled with volcanic rock (tezontle) (granulometry 2 to 3 mm) in an open hydroponic system with Steiner’s solution. The treatments consisted of nutrient solutions with increasing electrical conductivities: 2.0 (control), 2.3, 2.5 and 2.7 dS m^-1 obtained with the mixture of NaCl and Ca and Mg sulfates in the solutions applied by irrigation every 4 d starting at the flowering stage. Yield and number of fruits per plant were not affected. The concentration of proline in the root increased by 56, 111 and 97 % with electric conductivities of 2.3, 2.5 and 2.7 dS m-1, respectively. Leaf concentration of N, Ca, Na and Cl was not affected by increasing salinity, but P and Mg decreased by 55 and 52 %, respectively, in plants irrigated with solution of 2.7 dS m^-1, while K increased by 88 % and S by 117 %. No statistical differences were found in the weight, diameter, firmness and roundness index of fruit. The total soluble sugar content decreased by 18 % and the total soluble solids/tritable acidity ratio decreased by 11 % with solution of 2.7 dS m^-1. As the electrical conductivity increased the concentration of phenols, flavonoids, anthocyanins, antioxidant activity and percentage of inhibition decreased; only vitamin C increased. The applied increases in electric conductivity were not high enough to affect yield; salinity only increased the vitamin C content in fruits.