heterosis

noun

1. (countable, uncountable)The tendency of cross-breeding to produce an animal or plant with a greater hardiness than its parents; hybrid vigour.

   “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.”