F2

F2 is the second filial generation, produced by intercrossing (sibling-crossing) or self-pollinating F1 individuals (Acquaah 2012). Under classical Mendelian genetics, F2 progeny segregate at previously heterozygous loci in predictable ratios — a monogenic co-dominant trait segregates 1:2:1 genotypically. In cannabis, selfing an F1 Type II (B^T/B^D) plant yields an F2 segregating into ~25% Type I (THC-dominant), ~50% Type II (mixed), and ~25% Type III (CBD-dominant), a foundational result of de Meijer et al. (2003). The F2 is where breeders conduct extensive phenotype selection ("pheno-hunting") to recover desirable recombinant individuals for subsequent stabilization via inbreeding or backcrossing. F2 populations display maximum genetic variance, making them central to selection-based cannabis breeding (Clarke & Merlin 2013; Lewis et al. 2018). → See also: F1, BX, IBL, Phenotype.