Genotypic Screening Coupled with Foliar Fertilization for Enhanced Iron Bioavailability in Biofortified Pakchoi ( Brassica chinensis L.)

Iron (Fe) deficiency remains a prevalent nutritional challenge, particularly among populations with limited access to diverse and nutrient-rich diets. In this study, a greenhouse experiment was conducted to identify high-Fe-accumulating Pakchoi ( Brassica chinensis L.) genotypes. The effects of foliar Fe fertilization on Fe bioaccessibility and bioavailability were then evaluated using the in vitro digestion/Caco-2 cell model. The results showed that cultivating high-Fe-accumulating Pakchoi genotypes combined with applying precision Fe fertilization significantly increased Fe bioaccessibility (7.33–31.7%) and bioavailability (46.3–96.7%) compared to the non-biofortified control genotype ( MGQG ). Foliar Fe application improved or maintained the overall nutritional quality of Pakchoi genotypes. Consuming biofortified Pakchoi could contribute over eight times more to the daily reference intake (DRI) of Fe compared to the control. These findings highlight the potential of an integrated biofortification strategy, genotypic screening coupled with foliar fertilization, as a practical and efficient approach to mitigate health risks associated with “hidden hunger” in nutritionally vulnerable populations.