multiple heterosis

https://doi.org/10.1351/goldbook.14868
Higher fitness of an individual as a composite or summed effect of heterozygote superiority (heterosis) at each of a series of loci.
Source:
PAC, 2009, 81, 829. (Glossary of terms used in ecotoxicology (IUPAC Recommendations 2009)) on page 918 [Terms] [Paper]