Genotype
The complete DNA blueprint a plant inherits from its parents.
Genotype is the genetic instruction set; phenotype is what actually shows up in the plant. Strain names are marketing labels, not genotypes—the same name can hide different genetics, and clones are the only reliable way to preserve a specific genotype. Understanding this distinction cuts through a lot of cannabis folklore about 'true' strains.
Definition
Genotype refers to the complete set of genes a cannabis plant inherits from its parents — the DNA sequence present in every cell that encodes instructions for traits and function.
It is distinct from phenotype, which is the observable result of that genotype interacting with the environment (light, temperature, nutrients, stress, training). It is also distinct from chemotype, the classification of plants by the cannabinoids they actually produce (THC-dominant, CBD-dominant, balanced, etc.) Strong evidence [1].
What genotype determines
Genotype sets the potential range for:
- Cannabinoid synthesis: Whether a plant carries functional copies of THCA synthase or CBDA synthase genes determines whether it can produce THC, CBD, or other cannabinoids at all Strong evidence [2].
- Terpene production: A plant's genetic complement of terpene synthase enzymes governs which volatile compounds it is capable of making Strong evidence [3].
- Plant morphology: Height, leaf shape, branching structure, and growth habit.
- Flowering time and photoperiod response: Sensitivity to day length and speed of maturation.
- Disease and pest resistance: Inherited susceptibility or tolerance to common pathogens and insects.
What actually appears in the finished flower—the phenotype—depends on how the environment (and grower decisions) express that genetic potential. Two genetically identical plants grown under different conditions will show different phenotypes.
Genotype vs. strain name
A strain name like 'Blue Dream' or 'OG Kush' is a marketing label, not a precise genotype. Genetic fingerprinting studies have found that samples sold under the same strain name often carry different genetic profiles, and samples with different strain names can be genetically nearly identical Strong evidence [4][5].
If you want the same genotype twice, you need a clone—a cutting from a specific mother plant. Seeds, even from the same breeder and under the same name, create new and distinct genotypes because sexual reproduction shuffles genes from both parents.
Used in articles about
- Phenotype hunting: Selecting standout individual plants from a population of seeds or cuttings, each carrying a unique genotype.
- Clones: Preserving a single favoured genotype indefinitely through vegetative propagation.
- Landrace: Regional populations with distinctive genotypes shaped by local selection pressure over generations.
- Backcrossing: Breeding strategy that locks in specific genotype traits by crossing offspring back to a parent.
Sources
- Peer-reviewed Hillig, K. W., & Mahlberg, P. G. (2004). A chemotaxonomic analysis of cannabinoid variation in Cannabis (Cannabaceae). American Journal of Botany, 91(6), 966–975.
- Peer-reviewed Weiblen, G. D., Wenger, J. P., Craft, K. J., ElSohly, M. A., Mehmedic, Z., Treiber, E. L., & Marks, M. D. (2015). Gene duplication and divergence affecting drug content in Cannabis sativa. New Phytologist, 208(4), 1241–1250.
- Peer-reviewed Booth, J. K., Page, J. E., & Bohlmann, J. (2017). Terpene synthases from Cannabis sativa. PLOS ONE, 12(3), e0173911.
- Peer-reviewed Sawler, J., Stout, J. M., Gardner, K. M., Hudson, D., Vidmar, J., Butler, L., Page, J. E., & Myles, S. (2015). The genetic structure of marijuana and hemp. PLOS ONE, 10(8), e0133292.
- Peer-reviewed Schwabe, A. L., & McGlaughlin, M. E. (2019). Genetic tools weed out misconceptions of strain reliability in Cannabis sativa: implications for a budding industry. Journal of Cannabis Research, 1, 3.
How this page was made
Generation history
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