heterosis

From hetero- +‎ -osis.

heterosis (countable and uncountable, plural heteroses)

1. (genetics) The tendency of cross-breeding to produce an animal or plant with a greater hardiness than its parents; hybrid vigour.
   • 2018, Tim Flannery, Europe: A Natural History, page 159:

     Hybridisation can also result in heterosis - the scientific term for the production of ʽsuper fit’ hybrid individuals - many examples of which come from agriculture. Heterosis can be thought of as the opposite of inbreeding depression, the phenomenon whereby the offspring of individuals that are genetically too similar - for example, brother and sister - can suffer from debilitating maladies.

• heterotic

• isotheres, otherises, theorises