F1 Hybrid
Definition: An F1 hybrid is the first filial generation produced by crossing two genetically distinct parent plants. When both parents are true-breeding, F1 offspring tend to be uniform and often show hybrid vigor: faster growth, bigger yields and stronger stress resistance than either parent. Seeds collected from F1 plants, called F2, vary far more.
How F1 Hybrid works
The F stands for filial, from the Latin for son or daughter. Cross two plants and their seeds are F1. Cross two F1 siblings and you get F2, then F3, and so on. Each label tells you how many generations of sibling crossing a line has been through.
Hybrid vigor
Plant scientists call it heterosis. When parents are genetically different, offspring often outperform both, growing faster and handling heat, pests and mistakes better. Vegetable seed companies have relied on F1 hybrids for decades for this reason.
The cannabis catch
Classic F1 uniformity depends on parents that are homozygous, meaning each carries matching copies of its genes. Many cannabis parents are themselves unstable crosses, so a cannabis F1 can show more variation than an F1 tomato. Breeders who start from an IBL on each side produce the most consistent F1 seeds.
Why you should not save F1 seeds
- F2 plants reshuffle the parents’ genes, so traits split widely across offspring.
- Some F2s look like one grandparent, some like the other, many like neither.
- If you love an F1 plant, keep it as a clone or mother plant instead.