Core group (5)
(Other definitions for seeds that I've seen before include "favourites for the trophy?" , "Pips" , "Small hard fruits" , "top tennis players" , "More than one good player" .)
'core group' is the definition.
(cadre is a kind of core group)
This is all the clue.
(Other definitions for cadre that I've seen before include "Group of key people" , "Nucleus of key personnel" , "activist group" , "Raced (anag) -- small inner group of activists" , "Raced around with basic military unit" .)
(Other definitions for abs that I've seen before include "ratings?" , "stopping system" , "Exercise to improve these" , "Stomach muscles (abbr)" , "Some musculature" .)