Rejected a necessity when producing fruit (7)
I believe the answer is:
satsuma
'fruit' is the definition.
(I know that satsuma is a fruit)
'rejected a necessity when' is the wordplay.
'rejected' is a reversal indicator.
'necessity' becomes 'must' (I've seen this before).
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'a'+'must'+'as'='amustas'
'amustas' reversed gives 'SATSUMA'.
'producing' is the link.
(Other definitions for satsuma that I've seen before include "Loose-skinned tangerine" , "Japanese province and small orange" , "Segmented item" , "Type of small orange" , "Type of mandarin orange" .)