The most common and most likely answer to this crossword clue is the 10 letter word LOGANBERRY
I've seen this crossword clue in The Daily Telegraph
L
O
G
A
N
B
E
R
R
Y
Buddy explains!

The straight part
We know that "Fruit" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fruit = loganberry.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does LOGANBERRY mean?
LOGANBERRY noun- A hybrid berry, produced by crossing a raspberry with a blackberry, considered a species Rubus loganobaccus, a variety Rubus ursinus var. loganobaccus, or a nothospecies Rubus × loganobaccus.