# Breeder

> A breeder develops lines over generations with clear goals, large grow-outs, selection of both sexes, stability and herm testing, and honest lineage records.

- Canonical: https://genetixbay.com/knowledge/glossary/breeder.html
- Also written: breeders, plant breeder, cannabis breeder, seed breeder
- Glossary category: Grower slang and culture · Evidence: Grower practice
- 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"

A breeder, in the sense GenetixBay uses, is someone who develops a line over several generations toward a stated goal, rather than releasing a single cross. The work is mostly numbers and patience: grow many plants, select hard, keep and evaluate males, test for stability and [intersex](https://genetixbay.com/knowledge/glossary/hermaphrodite.md) tendency, and record everything.

## In practice

A breeder working a line might grow 100-300 plants per generation, keep the top 2-5% of females and a few carefully chosen males, cross or [backcross](https://genetixbay.com/knowledge/glossary/backcross.md) them, and repeat until the offspring are uniform enough to describe honestly. Before release, tester grows report [germination](https://genetixbay.com/knowledge/glossary/germination.md), [sex ratio](https://genetixbay.com/knowledge/glossary/sex-ratio.md), [herm rate](https://genetixbay.com/knowledge/glossary/herm-threshold.md) and spread of types. A breeder publishes what the line is and is not, including the faults.

Good breeders value males as much as females, because half the genetics of every seed comes from the father.

## Don't confuse with

- **Pollen chucker**: crosses and sells without the selection and testing.
- **Seed bank**: a vendor that sells seed, often from many breeders. Selling is not breeding.
- **Grower**: growing well and breeding well are different skills; many great growers never breed.

## Myth check

"Herms are just cannabis being cannabis." GenetixBay position: [herm-prone](https://genetixbay.com/knowledge/glossary/herm-prone.md) lines mostly come from breeding shortcuts (repeated selfing, careless feminising, untested crosses). A breeder culls for it. See [breeders vs pollen chuckers](https://genetixbay.com/knowledge/breeding/breeders-vs-pollen-chuckers.md) and [Mythbusters](https://genetixbay.com/knowledge/mythbusters.md).

## Related terms

[Pollen chucker](https://genetixbay.com/knowledge/glossary/pollen-chucker.md), [IBL](https://genetixbay.com/knowledge/glossary/ibl.md), [Selection](https://genetixbay.com/knowledge/glossary/selection.md), [Stud Book](https://genetixbay.com/knowledge/glossary/stud-book.md), [Test grow](https://genetixbay.com/knowledge/glossary/test-grow.md)

## Read more

- [Breeders vs pollen chuckers: what real cannabis breeding looks like](https://genetixbay.com/knowledge/breeding/breeders-vs-pollen-chuckers.md)
- [Selection and pheno hunting: sample sizes and scoring rubrics](https://genetixbay.com/knowledge/breeding/selection-pheno-hunting.md)