Pip (4)
(Other definitions for seedsman that I've seen before include "Supplier of nursery" , "Broadcaster" .)
'pip' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for seed that I've seen before include "Initiate the growth of" , "Grain" , "one of the top players" , "Basis for new plant" , "Pip for sowing" .)