Produced staple food, say (4)
I believe the answer is:
bred
'produced' is the definition.
(breeding is a kind of producing)
'staple food say' is the wordplay.
'staple food' becomes 'bread' (I've seen this before).
'say' shows a homophone (sound like).
'bread' sounds like 'BRED'.
(Other definitions for bred that I've seen before include "Brought forth" , "Gave rise to" , "Procreated" , "Very (music)" , "Reared" .)