Town produced nothing up north (4)
I believe the answer is:
'nothing up north' is the definition.
(northern dialect term for 'nothing')
'town produced' is the wordplay.
'produced' indicates anagramming the letters.
'town' is an anagram of 'NOWT'.
(Other definitions for nowt that I've seen before include "0", "Nothing (N. English)", "Northern 15 [NIX]", "Duck", "Town (anag.)".)