Related Clues:

• You may put it lower than dirt
• Most important
• Granny Smith throwaway
• Nucleus
• Center of an apple
• Apple's leftover
• Fundamental
• Nursery purchase
• Landscaper's supply
• Essential part
• Planting unit
• Tourney ranking
• Rank at Wimbledon
• Number one at Wimbledon, e.g.
• Granola bit