Endlessly cultivating dried fruit (6)
I believe the answer is:
raisin
'dried fruit' is the definition.
(raisin is a kind of dried fruit)
'endlessly cultivating' is the wordplay.
'endlessly' means to remove the last letter.
'cultivating' becomes 'raising' (raising is a kind of cultivating).
'raising' with its last letter taken away is 'RAISIN'.
(Other definitions for raisin that I've seen before include "Partially dried grape" , "Fruit for the Christmas cake" , "A dried grape, nice in cake" , "sultana, say" , "Cultivating" .)