Wordnet 3.0
VERB (1)
1. 
 breed animals or plants using parents of different races and varieties; 
- Example: "cross a horse and a donkey"- Example: "Mendel tried crossbreeding"- Example: "these species do not interbreed"[syn: crossbreed, cross, hybridize, hybridise, interbreed]
WordNet (r) 3.0 (2006):
hybridise
    v 1: breed animals or plants using parents of different races
         and varieties; "cross a horse and a donkey"; "Mendel tried
         crossbreeding"; "these species do not interbreed" [syn:
         crossbreed, cross, hybridize, hybridise,
         interbreed]