Aided development of a seed (5)
I believe the answer is:
eased
'aided' is the definition.
(easing is a kind of aiding)
'development of a seed' is the wordplay.
'development of' indicates an anagram (letters developed in another way).
'a'+'seed'='aseed'
'aseed' with letters rearranged gives 'EASED'.
(Other definitions for eased that I've seen before include "Moved carefully" , "Comforted" , "Lessened, pain or discomfort, say" , "Allayed" , "Alleviated" .)