# Open-pollinated

> Open-pollinated seed comes from a population left to cross freely among its own plants, without controlled pairs, which keeps a line's variation and type over generations.

- Canonical: https://genetixbay.com/knowledge/glossary/open-pollinated.html
- Also written: OP, open pollination, open-pollinated seed, OP seed, open pollinated
- 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"

Open-pollinated (OP) seed is produced by letting many plants of one population cross freely among themselves, by wind or by hand pollen mixes, instead of crossing one chosen female with one chosen male. Grown in isolation from other types, an OP population keeps its character from generation to generation while holding plenty of internal variation.

## In practice

Most [landraces](https://genetixbay.com/knowledge/glossary/landrace.md) were maintained this way for centuries: a farmer saved seed from the best plants of a field each year. OP lines are resilient and adaptable because they carry many [alleles](https://genetixbay.com/knowledge/glossary/allele.md). They are also the practical way to preserve a population, as opposed to a single clone.

Doing it well means a large enough population. Seed saved from two or three plants each year narrows the [gene pool](https://genetixbay.com/knowledge/glossary/gene-pool.md) fast through [genetic drift](https://genetixbay.com/knowledge/glossary/genetic-drift.md) and [inbreeding](https://genetixbay.com/knowledge/glossary/inbred-line.md). [Seed banks](https://genetixbay.com/knowledge/glossary/seed-bank.md) maintaining OP [accessions](https://genetixbay.com/knowledge/glossary/accession.md) aim for dozens of parents or more per regeneration.

## Don't confuse with

- **F1 hybrid**: a controlled cross between two parents, usually uniform; its seed does not stay true.
- **Landrace**: a type of OP population with local adaptation and history; not every OP line is a landrace.
- **Uncontrolled pollination**: a room with a stray herm is accidental pollination, not an OP programme.

## Related terms

[Landrace](https://genetixbay.com/knowledge/glossary/landrace.md), [Heirloom](https://genetixbay.com/knowledge/glossary/heirloom.md), [IBL](https://genetixbay.com/knowledge/glossary/ibl.md), [Gene pool](https://genetixbay.com/knowledge/glossary/gene-pool.md), [Genetic drift](https://genetixbay.com/knowledge/glossary/genetic-drift.md)

## Read more

- [Polyhybrids vs landraces: what each gives a breeder](https://genetixbay.com/knowledge/breeding/polyhybrids-vs-landraces.md)
- [Landraces of the world: an overview](https://genetixbay.com/knowledge/genetics-history/landraces-of-the-world.md)

## Sources

1. Allard RW. 1999. Principles of Plant Breeding, 2nd edition. John Wiley & Sons, New York. ISBN 978-0-471-02309-0
2. Villa TCC, Maxted N, Scholten M, Ford-Lloyd B. 2005. Defining and identifying crop landraces. Plant Genetic Resources 3(3):373-384. https://doi.org/10.1079/PGR200591