Genetics & Breeding
The first-generation cross of two distinct, stable parent lines — typically vigorous and uniform (hybrid vigor).
F1 (first filial generation) is the first cross between two distinct, true-breeding parent lines. F1 hybrids often display 'hybrid vigor' (heterosis): they grow faster, yield more, and are more uniform than either parent. However, if you breed two F1 plants together, the F2 generation splits into a wide range of phenotypes. This is why reproducing an F1 hybrid reliably requires maintaining both original parent lines.