Indicating ‘first filial’ generation, denoting offspring from genotypically (see genotype) distinct parents.
Note: F2 denotes offspring resulting from mating (inbreeding) of individuals from F1. The term may be extended to F3 and beyond.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 753 (https://doi.org/10.1515/pac-2015-1202)