Possible Clues:

• Edible white or yellow root
• Rutabaga, e.g
• Watch what you eat?
• Vegetable with greens
• Source of some greens
• Might the Swede fasten the cart track upside down?
• Rotate one vegetable, so to speak, for another
• Vegetable staple perhaps, with furrow turned over
• Vegetable with round white root
• 'Root vegetable, yellow or white (6)'