Vegetable from standard crop (7)
I believe the answer is:
parsnip
'vegetable' is the definition.
(parsnip is a type of vegetable)
'standard crop?' is the wordplay.
'standard' becomes 'par' (standard of play in golf).
'crop?' becomes 'snip' (synonyms).
'par'+'snip'='PARSNIP'
'from' is the link.
(Other definitions for parsnip that I've seen before include "Type of root veg" , "A white root vegetable" , "Yellow root vegetable" , "Pale carrot-like vegetable" , "Pips ran oddly through the vegetable" .)