If toi put nourriture colouring in a potato seed will the potato grow purple?

that would be awesome

no it might turn blue toi didnt say purple nourriture die so it might be rose ou green i think toi know what i mean

No, if you're only working with the seeds toi would have to change the potatoes' genes.
But toi might get some effect if toi constantly water the plant with heavily dyed water.(or toi can par potatos that are already purple)