Country pear is rotten (6)
I believe the answer is:
persia
'country' is the definition.
(I know that Persia is a historical country)
'pear is rotten' is the wordplay.
'rotten' indicates an anagram.
'pear'+'is'='pearis'
'pearis' with letters rearranged gives 'PERSIA'.
(Other definitions for persia that I've seen before include "Aspire to this old country" , "It's now known as Iran" , "Iran, formerly" , "Praise be to ancient Iran" , "Old name for country at 25 Across" .)