Rewarding vegetable (6)
I believe the answer is:
carrot
'rewarding vegetable' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for carrot that I've seen before include "The vegetable to induce" , "One prov. used to encourage" , "Orangey vegetable" , "Obstacle in race" , "Root vegetable" .)