The phrase "hybrid vigor" refers to the phenomenon where the offspring of two different breeds or varieties of organisms tend to be healthier, stronger, or more productive than their parents. Full definition
The F1B generation is still close enough in the breeding tree to benefit from hybrid vigour. (dreamydoodles.com)
In fact farmers so recognise the benefit of hybrid vigour that much of the meat we eat, milk we drink and eggs we boil are from crossbreeds. (dogbreedhealth.com)
Poodles and Goldens are both breeds within the same species, so hybrid vigour would not result. (grcc.net)