Iron Biofortification of Greenhouse Cherry Tomatoes Grown in a Soilless System

Iron (Fe) biofortification is a strategy to increase the amount of iron in food crops. The goal of this work was to assess the possibility of maximizing the Fe content in cherry tomatoes grown in a soilless system. The cultivar Creativo was grown with three concentrations of Fe (as Fe-HBED) in the nutrient solution (0.022, 1, and 2 mmol L−1), and received further foliar applications of the element (as Fe-DTPA) at 0, 250, and 500 µmol L−1. The addition of 2 mmol Fe L−1 to the nutrient solution, together with foliar sprays at 500 µmol Fe L−1, induced the highest increase in fruit Fe concentration in clusters 1 and 2 (by 163% and 190%, respectively). The Fe added to the nutrient solution increased the fruit dry matter (up to +10.21%) but decreased the fruit’s fresh weight (up to −11.06%). The higher Fe concentrations provided to the crop synergistically increased the contents of other minerals (i.e., K, Mg, Na, and Zn), along with the fruit’s titratable acidity and soluble solids content, improving multiple functional and quality traits of the cherry tomatoes. These results show that Fe biofortification of cherry tomatoes can be effective to address Fe deficiency while obtaining high-quality products.