Just beat seed (3)
I believe the answer is:
pip
I believe this clue is a double definition.
'just beat' is the first definition.
(as in pipping someone to the post)
'seed' is the second definition.
(as in a fruit pip)
(Other definitions for pip that I've seen before include "Dickens hero" , "Greenwich time signal" , "Narrowly defeat" , "Defeat at the last moment - . . . at the post" , "Annoyed" .)