Crop produced by real cultivation (6)
I believe the answer is:
barley
'crop' is the definition.
(I've seen this before)
'by real cultivation' is the wordplay.
'by real' anagrams to 'BARLEY'.
Though, I am not clear how the anagram is indicated.
'produced' acts as a link.
Can you help me to learn more?
(Other definitions for barley that I've seen before include "Cereal used in beer" , "Grain used in brewing" , "Grain used in making beer" , "Cereal grass" , "Hardy cereal" .)