Noun
F1 hybrid (plural F1 hybrids)
(genetics) The first filial generation of seeds or animal offspring, which are usually vigorous and uniform. Produced by crossing two distinctly different parents.
Page 257. * Single cross hybrids — result from the cross between two true breeding organisms and produces an F1 generation called an F1 hybrid (F1 is short for Filial 1, meaning "first offspring"). Source: Internet