Foliar iodine application: a strategy for tomato biofortification and yield optimization.

Iodine (I) is a beneficial micronutrient for crop plants and essential for human health, yet approximately two billion people worldwide suffer from I deficiency, resulting in significant health issues. Agricultural soils often lack sufficient I, resulting in crops with low I content. However, tomatoes have shown potential to accumulate I when supplemented externally, making them an ideal candidate for I biofortification, particularly as an alternative to iodized salt for individuals on low-sodium diets. This two-year greenhouse pot experiment evaluated the effectiveness of foliar application of potassium iodide (KI) in biofortifying two commercial tomato hybrids. Different concentrations of I (0, 1, 3, 6, and 9 mM/plant) were applied as foliar treatments to assess their effects on physiological parameters, yield attributes, and quality traits, especially I enrichment in tomato fruit. The results demonstrated that foliar application of KI significantly increased fruit I contents at concentrations that also promoted overall plant growth and development. These findings underscored the efficient translocation of I through the phloem in tomatoes. I enrichment in tomato fruits ranged up to 5.27 mg/kg, exceeding the recommended daily allowance (RDA) of 150 μg/day. Even lower doses of 1–3 mM KI were effective in achieving significant I enrichment suitable for biofortification programs. In conclusion, tomato emerged as an excellent candidate for agronomic biofortification with I due to the practicality, and affordability of foliar application. The study highlights the potential of foliar I application as a feasible strategy for addressing global I deficiency, emphasizing its suitability for widespread adoption by farmers. [ABSTRACT FROM AUTHOR]