Fruit, no end, for ruler (6)
I believe the answer is:
sultan
'ruler' is the definition.
(sultan is a kind of ruler)
'fruit no end' is the wordplay.
'fruit' becomes 'sultana' (sultana is a kind of fruit).
'no end' means to remove the last letter.
'sultana' with its final letter removed is 'SULTAN'.
'for' acts as a link.
(Other definitions for sultan that I've seen before include "Muslim ruler" , "Chicken" , "One governs" , "one ruling the roost?" , "Ruler of Brunei" .)