Genotype, Phenotype, and Phenotypic Plasticity
Separate inherited genotype from the phenotype expressed at a particular stage, place, treatment, and sampling method.
Educational reference · evidence, sources, and limits shown below
Separate inherited genotype from the phenotype expressed at a particular stage, place, treatment, and sampling method.
Terms to know
- Genotype
- An individual’s inherited DNA sequence state, either genome-wide or at specified loci.
- Phenotype
- An observed or measured characteristic produced by biology under defined conditions.
- Plasticity
- Capacity of one genotype to express different phenotypes across environments or development.
- Reaction norm
- Pattern of a genotype’s phenotype across an environmental gradient or set of environments.
Core science
Phenotype is not genotype made visible without interference. A useful model is phenotype = genotype + environment + genotype-by-environment interaction + development + measurement error. Plant age, node position, reproductive status, canopy location, root condition, and prior stress can change the measured outcome.
Plasticity can be adaptive, neutral, or harmful. The same clone may change branch number under different spectra, rooting success under different propagation environments, or metabolite concentration across canopy positions and harvest dates. Such changes do not automatically indicate genetic contamination.
A phenotype becomes comparable only after the protocol defines the organ, stage, environment, unit, sampling intensity, and data treatment. Photographs are valuable records but rarely replace quantitative measurements or chemistry.
Why this matters in cultivation
- Use clones as paired environmental tests only when identity and health are confirmed and the ramets are randomized. Otherwise source-plant position, cutting size, or pathogen status can masquerade as treatment plasticity.
- Preserve unusual phenotypes for retest before naming a new line. A stable genetic difference should repeat under common conditions or be supported by identity testing.
Measure and record
Genotype identity
Clone or seed-family ID, source, generation, markers if used, and custody.
Phenotype definition
Trait, organ, stage, position, unit, instrument, and scoring threshold.
Environment
Light, photoperiod, air and root-zone conditions, nutrition, water, density, and stress.
Development
Age, node count, floral stage, days from transition, and prior treatment.
Repeat test
Replicates, randomization, control genotype, second run, and outcome consistency.
Common misconceptions
Correction: Shared genotype does not erase environmental, developmental, or biological variation.
Correction: Mislabeling, plasticity, disease, nutrition, and sampling should be tested first.
Correction: Stability requires repeated expression and an explicit test environment.
Evidence limits
Cannabis plasticity studies cover limited genotypes and traits. Common-environment retesting can separate some causes, but it does not prove the molecular mechanism.
Related encyclopedia topics
- THC-ENC-020, THC-ENC-080, THC-ENC-141-147, THC-ENC-159, and THC-GROW-030.
Source notes
- Campbell L.G. et al. (2019). Phenotypic plasticity influences the success of clonal propagation in industrial pharmaceutical Cannabis sativa. PLOS ONE 14:e0213434.
- Campbell B.J. et al. (2019). Genotype x environment interactions of industrial hemp cultivars. Agrosystems, Geosciences & Environment 2:1-11.
- Stack G.M. et al. (2023). Correlations among morphological and biochemical traits in high-cannabinoid hemp. Plant Direct 7:e503.
- THC Cannabis Plant Science Source Packet v1.1 (project source, May 2026).
This lesson summarizes the source material and its evidence limits for education. Use direct measurement, controlled comparison, and the cited sources when conditions differ or a decision carries meaningful risk.