Yellow variety of melon (5)
I believe the answer is:
lemon
'yellow' is the definition.
(I know that lemon is a type of yellow)
'variety of melon' is the wordplay.
'variety of' is an anagram indicator.
'melon' with letters rearranged gives 'LEMON'.
(Other definitions for lemon that I've seen before include "Dab" , "Melon is another fruit" , "Sharp-tasting fruit" , "Fruit squeezed on Pancake Day?" , "Fruit high in vitamin C" .)