How about a system where you could farm better crops that other people by selecting good plants to reproduce instead of the bad ones. Think of it this way if you harvest seeds from successful plants you get better grade seeds but if you harvest seeds from rotten plants you get lower grade seeds that produce lower grade plants. Some variables may be: Calorie count in food, grow time, success rate, seed count... Maybe by planting a plant with good grow time next to a plant with good success rate could have seeds that follow this sorta formula: ([(plant a's grow rate)+(plant b's grow rate)]/2)+(0 to [(1.5)Better plant's grow rate]) this would give you a chance to breed better plants making good seeds have value in game.