F1, F2, Fn 1 topic · 1 source Science› Biotechnology and GeneticsFood BiotechnologySubsequent hybrid generations, counting from the F1. Thus, for example, F4 describes the progeny of the F3, which is the progeny of the F2 generation, where all progeny are derived from intercrossing or self-fertilization.UN Food and Agriculture Organization — Glossary of Biotechnology for Food and Agriculture Cite