# Diploid

> A diploid organism carries two complete sets of chromosomes, one from each parent; normal cannabis is diploid with 2n = 20.

- Canonical: https://genetixbay.com/knowledge/glossary/diploid.html
- Also written: diploidy, 2n, diploid plant
- 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"

A diploid plant carries two full sets of [chromosomes](https://genetixbay.com/knowledge/glossary/chromosome.md) in its body cells, one set from the pollen parent and one from the seed parent. Normal cannabis is diploid with 2n = 20 chromosomes. Its pollen and ovules are haploid (n = 10), so fertilisation restores the diploid number.

## In practice

Diploidy is why every gene comes in two copies and why simple [Mendelian ratios](https://genetixbay.com/knowledge/glossary/mendelian-inheritance.md) work. With two [alleles](https://genetixbay.com/knowledge/glossary/allele.md) per [locus](https://genetixbay.com/knowledge/glossary/locus.md) a plant is either [homozygous](https://genetixbay.com/knowledge/glossary/homozygous.md) or [heterozygous](https://genetixbay.com/knowledge/glossary/heterozygous.md), and a heterozygote passes each allele to half its gametes.

Almost all cannabis grown today is diploid. [Polyploid](https://genetixbay.com/knowledge/glossary/polyploid.md) plants (triploids with three sets, tetraploids with four) are made deliberately, for example to produce mostly seedless triploid crops, and they do not follow diploid ratios.

## Units and formula

Cannabis: haploid n = 10; diploid 2n = 20; triploid 3n = 30; tetraploid 4n = 40.

## Don't confuse with

- **Polyploid**: more than two chromosome sets.
- **Haploid**: one set, as in pollen and egg cells.
- **Dioecious**: separate male and female plants. Cannabis is both diploid and [dioecious](https://genetixbay.com/knowledge/glossary/dioecious.md), but the two words describe different things.

## Related terms

[Polyploid](https://genetixbay.com/knowledge/glossary/polyploid.md), [Chromosome](https://genetixbay.com/knowledge/glossary/chromosome.md), [Allele](https://genetixbay.com/knowledge/glossary/allele.md), [Homozygous](https://genetixbay.com/knowledge/glossary/homozygous.md), [Heterozygous](https://genetixbay.com/knowledge/glossary/heterozygous.md)

## Read more

- [Mendelian genetics for growers, with Punnett squares](https://genetixbay.com/knowledge/breeding/mendelian-genetics-for-growers.md)

## Sources

1. Divashuk MG, Alexandrov OS, Razumova OV, Kirov IV, Karlov GI. 2014. Molecular cytogenetic characterization of the dioecious Cannabis sativa with an XY chromosome sex determination system. PLoS ONE 9(1):e85118. https://doi.org/10.1371/journal.pone.0085118
2. Kurtz LE, Brand MH, Lubell-Brand JD. 2023. Gene dosage at the autoflowering locus effects flowering timing and plant height in triploid cannabis. Journal of the American Society for Horticultural Science 148(2):83-88. https://doi.org/10.21273/JASHS05293-23