Produced by crossbreeding (6)
I believe the answer is:
hybrid
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">produced by crossbreeding</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for hybrid that I've seen before include "A composite of mixed origin" , "Plant that is the offspring of two different species" , "Of mixed character" , "Produced by crossbreeding" , "Offspring of mixed parents" .)