The Response of Yield and Accumulated Iodine in Melon Affected by Biofortification With Potassium Iodide in Variance Rates Under Greenhouse Conditions

This study examined the impact of potassium iodide (KI) application on iodine accumulation, growth rate, and yield quality in melons. A 2 × 5 factorial experiment was conducted in a completely randomized design with three replications, examining two factors: (1) melon cultivar (Fujisawa, designated as Fuj, and Sweet D25, designated as Swe) and (2) KI application rates (0.0, 4.5, 9.0, 13.5, and 18.0 mg/plant/time). The results showed that KI application at 9.0 mg/plant/time resulted in the highest fresh fruit weight and largest fruit size (both width and length) for both cultivars. In contrast, KI concentrations of 13.5 and 18.0 mg/plant/time reduced yield and fruit size, likely due to excessive iodine. Iodine accumulation was highest at 9.0 mg/plant/time, reaching 108.99 µg/100 g FW in Fuj and 62.22 µg/100 g FW in Swe, with these levels meeting the recommended daily iodine intake for humans. Besides, iodine and nutrient accumulation varied between cultivars: in Fuj, iodine was negatively correlated with potassium, whereas in Swe, iodine showed a positive correlation with potassium. These findings may inform biofortification strategies with iodine in melons and other plant species.