Source : Webster's Revised Unabridged Dictionary (1913)

Dysgenesis \Dys*gen"e*sis\, n. [Pref. dys- + genesis.] (Biol.)
   A condition of not generating or breeding freely;
   infertility; a form homogenesis in which the hybrids are
   sterile among themselves, but are fertile with members of
   either parent race.

Source : WordNet®

dysgenesis
     n : infertility between hybrids