Man would develop ultimate in quince jams, a key part of sustainable farming (8)
I believe the answer is:
hedgerow
'man' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'would develop ultimate in quince jams a key part of sustainable farming' is the wordplay.
I cannot really understand how this works, but
'would' could be 'd' (as in 'we'd' - 'we would') and 'd' is found in the answer.
'key' could be 'g' (musical key) and 'g' is found within the answer.
'part' could be 'row' (row is a kind of part) and 'row' is present in the answer.
The remaining letters 'hee' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for hedgerow that I've seen before include "Growth around field" , "Greenery between fields" , "Living boundary between fields" , "Field boundary" , "Field border" .)