Impact of a plant-derived biostimulant and iron biofortification alone or in combination on quality and compositional traits of three carrot cultivars differing in their root color

This experiment addressed the response of the carrots ‘Dordogne’ (orange roots), ‘Mello Yello’ (yellow), and ‘Purple Sun’ (purple) to different foliar treatments, over two seasons (SI and SII). Plants were treated with either a plant-derived biostimulant (PDB, T1), a biofortifying solution (FeSO 4 , T2), or their combination (T3) and compared to controls. Root carotenoids peaked in ‘Dordogne’ (9284 and 8104 μg 100 g −1 FW in SI and SII, respectively) while ‘Purple Sun’ had the highest minerals and hydroxycinnamic acids levels (64.7 and 80.5 mg 100 g −1 FW). In both seasons, T3 best promoted the root accumulation of iron (+18.2 and + 39.1% in SI and SII), carotenoids (+35.3 and + 35.6%), hydroxycinnamic acids (+73.5 and + 40.9%), and anthocyanins (+30.0 and + 25.6%). Our results highlight the role of different carrot typologies toward the dietary diversification of minerals and phytochemicals, while promoting the use of PDBs and Fe-biofortification to further enhance their nutritional traits.