# Topophysis

> Topophysis is the tendency of cuttings to keep traits linked to the position on the mother plant they were taken from, so cuts from different parts can behave differently.

- Canonical: https://genetixbay.com/knowledge/glossary/topophysis.html
- Also written: position effect, cutting position effect, topophytic effect, branch position effect
- Glossary category: Genetics and breeding · Evidence: Supported
- 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"

Topophysis is a position effect in [vegetative propagation](https://genetixbay.com/knowledge/glossary/cloning.md): a cutting can carry on behaving like the part of the plant it came from for some time. Cuttings from lower, shaded or older branches may root, grow or flower differently from cuts taken at the top, even though they share the same [genotype](https://genetixbay.com/knowledge/glossary/genotype.md).

## In practice

Cannabis growers see it as variation between clones of one mother. Cutting position measurably changes rooting in cannabis stem cuttings (Caplan et al. 2018). Growers also report differences in vigour and early growth that [fade](https://genetixbay.com/knowledge/glossary/senescence.md) after a cycle or two.

House position: cuts taken from different parts of a plant can behave differently. That may or may not involve mutation. Practical advice is to take cuts from consistent locations on the mother (similar height, branch age and size) so that clones start alike, and to judge a cultivar on several clones, not one.

## Don't confuse with

- **Genetic drift**: random change in [allele](https://genetixbay.com/knowledge/glossary/allele.md) frequencies in seed populations; clones do not drift.
- **Somatic mutation**: a real DNA change in one branch; rare, and a mutation doesn't mean a loss.
- **Pathogen decline**: a cut that gets worse every cycle is a disease or care problem, not position.

## Related terms

[Genetic drift](https://genetixbay.com/knowledge/glossary/genetic-drift.md), [Somaclonal variation](https://genetixbay.com/knowledge/glossary/somaclonal-variation.md), [Mutation](https://genetixbay.com/knowledge/glossary/mutation.md), [Clone-only](https://genetixbay.com/knowledge/glossary/clone-only.md)

## Read more

- [Clone-only cuts and how to preserve them](https://genetixbay.com/knowledge/breeding/clone-only-preservation.md)

## Sources

1. Caplan D, Stemeroff J, Dixon M, Zheng Y. 2018. Vegetative propagation of cannabis by stem cuttings: effects of leaf number, cutting position, rooting hormone, and leaf tip removal. Canadian Journal of Plant Science 98(5):1126-1132. https://doi.org/10.1139/cjps-2018-0038
2. Adamek K, et al. 2022. Accumulation of somatic mutations leads to genetic mosaicism in cannabis. The Plant Genome 15(1):e20169. https://doi.org/10.1002/tpg2.20169