# P1

> P1 is the parental generation: the two original plants crossed to start a breeding project, whose offspring are the F1.

- Canonical: https://genetixbay.com/knowledge/glossary/p1.html
- Also written: P1 generation, parental generation, P generation, parental line
- Glossary category: Genetics and breeding · Evidence: Established
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

P1 (the parental generation) is the pair of plants crossed to start a breeding programme. Their seed is the [F1](https://genetixbay.com/knowledge/glossary/f1.md), the F1 crossed among itself gives the [F2](https://genetixbay.com/knowledge/glossary/f2.md), and so on. In some texts the parents are written simply as P.

## In practice

In cannabis the P1 pair is usually one selected female (often a clone) and one selected male. Documenting them properly is the foundation of any honest lineage: name or GB-style ID of each parent, where they came from, [photos](https://genetixbay.com/knowledge/glossary/photoperiod.md), test results and the date of the cross. Without that, every later generation inherits a guess.

The P1 parents do not have to be inbred. When they are [heterozygous](https://genetixbay.com/knowledge/glossary/heterozygous.md) [hybrids](https://genetixbay.com/knowledge/glossary/hybrid.md) themselves, as most modern cannabis is, the "F1" is already variable. Breeders then talk about F1s loosely, but genetically that seed behaves more like an F2.

## Don't confuse with

- **F1**: the offspring of P1, not the parents.
- **Recurrent parent**: in a [backcross](https://genetixbay.com/knowledge/glossary/backcross.md) programme, the P1 plant crossed back into again and again.
- **Mother plant**: a horticultural term for a plant kept for cuttings. A mother can be a P1, but not every P1 is kept as a mother.

## Related terms

[F1](https://genetixbay.com/knowledge/glossary/f1.md), [F2](https://genetixbay.com/knowledge/glossary/f2.md), [Filial generation](https://genetixbay.com/knowledge/glossary/filial-generation.md), [Hybrid](https://genetixbay.com/knowledge/glossary/hybrid.md), [Backcross](https://genetixbay.com/knowledge/glossary/backcross.md)

## Read more

- [F1, F2, F3 explained: what filial generations really mean](https://genetixbay.com/knowledge/breeding/f1-f2-f3-explained.md)

## Sources

1. Allard RW. 1999. Principles of Plant Breeding, 2nd edition. John Wiley & Sons, New York. ISBN 978-0-471-02309-0