Key topic for debate, producing strong feeling (7)
I believe the answer is:
emotion
'strong feeling' is the definition.
(I've seen this in another clue)
'key topic for debate' is the wordplay.
'key' becomes 'e' (musical key).
'topic for debate' becomes 'motion'.
'e'+'motion'='EMOTION'
'producing' acts as a link.
(Other definitions for emotion that I've seen before include "reaction" , "Surprise, perhaps" , "eg Anger, fear, joy" , "sense" , "Feeling - sentiment" .)