Coffee cultivated primarily in part of Asia (7)
I believe the answer is:
arabica
'coffee' is the definition.
(type of coffee plant)
'cultivated primarily in part of asia' is the wordplay.
'primarily' suggests taking the first letters.
'in' means one lot of letters goes inside another.
'part of asia' becomes 'Arabia' (Arab region of Asia).
The first letter of 'cultivated' is 'c'.
'c' going within 'arabia' is 'ARABICA'.
(Other definitions for arabica that I've seen before include "Variety of coffee beans" , "Type of coffee bean" , "Shrubby tree of tropical Africa cultivated for coffee" , "Variety of coffee bean" , "African tree cultivated for coffee" .)