Reproduce black woodwind instrument (5)
I believe the answer is:
breed
'reproduce' is the definition.
(I know that breed is a more specific form of the action reproduce)
'black woodwind instrument' is the wordplay.
'black' becomes 'b' (as in pencil classifications).
'woodwind instrument' becomes 'reed' (reed is a kind of woodwind instrument).
'b'+'reed'='BREED'
(Other definitions for breed that I've seen before include "eg Merino" , "Strain; reproduce" , "Livestock classification" , "Special variety of domesticated animal" , "Produce young" .)