# Cannabis growing and breeding glossary

> Plain-language definitions of the growing, botany and breeding terms used across GenetixBay, with notes where the popular meaning differs from the scientific one.

- Canonical: https://genetixbay.com/knowledge/basics/glossary.html
- Category: Basics · Level: Beginner
- Evidence: Established · Status: Draft: awaiting expert review
- Stage: Any stage · Systems: Any system
- Updated: 2026-10-31 · Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay Knowledge Base (genetixbay.com/knowledge)"

## Questions and answers

**What does F1 mean in cannabis?** F1 in cannabis means the first filial generation: the offspring of crossing two parents, written female first (female x male). F1s of unrelated parents typically show the strongest [hybrid vigour](https://genetixbay.com/knowledge/glossary/heterosis.md), outperforming the parents' average. Crossing F1 siblings gives the F2, where allele pairs segregate and create much more variation. In cannabis, 'F2' usually means sibling-crossed F1s, not selfed plants.

**What is a phenotype vs a genotype?** A genotype is a cannabis plant's genetic make-up; a phenotype is what you actually observe, which is the genotype plus the environment plus their interaction. Two clones share a genotype but can look different in different rooms. Growers also use 'pheno' loosely to mean one individual plant from a seed lot, as in 'the #4 pheno', which is really one distinct genotype among siblings.

**What is an IBL?** An IBL (inbred line) is a cannabis population inbred over several generations until it breeds fairly true, so seedlings come out much more alike than in a hybrid. No fixed number of generations defines an IBL, so treat the label as a breeder's claim and check the line's documentation. Close inbreeding can also cause [inbreeding depression](https://genetixbay.com/knowledge/glossary/inbreeding-depression.md), as hidden harmful recessives become homozygous.

**What does S1 mean?** S1 means seed from a cannabis plant pollinated by itself (selfed), usually by reversing one branch or a clone of the same plant so it makes pollen. Because that pollen comes from a female, S1 seed is nearly all female. GenetixBay treats repeated selfing, such as S1 on S1, as a main source of herm-prone lines, so an S1 label deserves a close look at the breeder's grow-out data.

**What is a clone-only?** A clone-only, or 'cut', is a selected individual cannabis plant kept only as clones, so the name refers to one specific genotype rather than a seed line. Every rooted cutting is genetically identical to its source, barring rare mutations, and the cut is maintained by keeping mother plants vegetative. Because no seed version exists, the genotype survives only as long as someone keeps it alive.

**What is a chemotype or chemovar?** A chemotype or chemovar is a cannabis plant classified by its chemistry rather than its name or looks. The standard scheme has five types: chemotype I is THC dominant, II mixes THC and CBD, III is CBD dominant, IV is CBG dominant and V is near cannabinoid-free. The THC and [CBD synthase](https://genetixbay.com/knowledge/glossary/cbda-synthase.md) alleles behave close to codominant, so a plant carrying one of each tends toward the mixed type II.

**What does BX mean?** BX means backcross: offspring crossed back to one of its own parents. The generations are numbered BX1, BX2 and so on, also written BC1 and BC2. Breeders use backcrosses to steer a line back toward one parent's traits. The convention for writing any cannabis cross lists the female first (female x male), so the pedigree shows which way each backcross was made.

**Short answer.** This is the shared vocabulary for GenetixBay articles and courses. Where growers use a word differently from botanists, both meanings are given. Terms are grouped, then alphabetical within each group.

## Plant and botany

| Term | Meaning |
|---|---|
| **Achene** | The botanical name for a cannabis "seed": one seed inside a hard fruit wall. |
| **Bract** | The leafy sheath around each [female flower](https://genetixbay.com/knowledge/glossary/pistillate-flower.md); most glandular trichomes sit here. Growers often call it the **calyx** (botanically, the calyx is a much reduced structure underneath). |
| **Cola** | A terminal flower cluster on a main stem or branch. |
| **Dioecious** | Separate male and female plants. The natural, long-stable state of cannabis, and of essentially all drug-type cannabis. |
| **Monoecious** | Male and female flowers on one plant, bred in on purpose in some modern [hemp cultivars](https://genetixbay.com/knowledge/glossary/hemp.md). Not the norm for cannabis, and not the same as a stressed [hermaphrodite](https://genetixbay.com/knowledge/glossary/hermaphrodite.md). |
| **Hermaphrodite (hermie, intersex)** | A genetic female that also makes [pollen sacs](https://genetixbay.com/knowledge/glossary/anther.md) or bare anthers ("bananas", "nanners"). An unwanted outlier in a dioecious crop, mainly the result of poor breeding (repeated selfing, careless feminising); stress reveals it. Cull, don't breed from it. See [hermaphrodites](https://genetixbay.com/knowledge/diagnosis/hermaphrodites.md). |
| **Node / internode** | Node: where leaves and branches attach. Internode: stem between nodes. |
| **Pistil / stigma** | Growers say "pistils" or "hairs"; strictly, the visible hairs are stigmas. |
| **Pre-flower** | Solitary flowers at the nodes before full flowering; used to sex plants. |
| **Trichome** | A hair-like outgrowth. Glandular [capitate-stalked trichomes](https://genetixbay.com/knowledge/glossary/capitate-stalked-trichome.md) make cannabinoids and terpenes. |

## Life cycle and cultivation

| Term | Meaning |
|---|---|
| **Autoflower (day-neutral)** | Flowers by age, not night length. |
| **Clone (cutting)** | A rooted piece of one plant; genetically identical to the source, barring rare mutations. |
| **Mother** | A plant kept vegetative as a source of clones. |
| **Photoperiod** | Flowers in response to long nights. |
| **Re-veg** | Returning a flowering plant to vegetative growth by restoring long days. |
| **Sinsemilla** | "Without seed": unpollinated female flower. |
| **Stretch** | Rapid elongation in the first 2-3 weeks of flower. |

## Genetics

| Term | Meaning |
|---|---|
| **Allele** | One version of a gene. A [diploid plant](https://genetixbay.com/knowledge/glossary/diploid.md) carries two alleles per gene. |
| **Dominant / recessive** | A dominant allele shows its effect with one copy; a recessive one needs two. |
| **Codominant** | Both alleles show; the heterozygote is a blend of both effects. THC/CBD synthase alleles behave close to this [3]. |
| **Genotype** | The genetic make-up. |
| **Phenotype** | What you observe: genotype plus environment plus their interaction. Growers say "pheno" to mean one individual plant from a seed lot ("the #4 pheno"). |
| **Chemotype / chemovar** | Plant classified by chemistry. Chemotype I (THC dominant), II (THC and CBD mixed), III (CBD dominant), IV (CBG dominant), V (near cannabinoid-free) [3]. |
| **Heterozygous / homozygous** | Two different alleles / two identical alleles at a gene. |
| **Heritability** | The share of observed variation in a trait that is due to genetic differences, in a given population and environment [1]. |
| **Hybrid vigour (heterosis)** | Offspring outperforming the parents' average, typically strongest in F1s of unrelated parents. |
| **Inbreeding depression** | Loss of vigour and fertility after close inbreeding, as hidden harmful recessives become homozygous. |
| **Locus (plural loci)** | A position on a chromosome; usually a gene. |
| **Segregation** | Separation of allele pairs into gametes, which creates variation in F2 and later generations [2]. |

## Breeding notation

| Term | Meaning |
|---|---|
| **P1, P2** | Parents of a cross. Convention: female listed first (female x male). |
| **F1** | First filial generation: offspring of two parents. |
| **F2, F3...** | Offspring of F1 x F1 (or [sibling crosses](https://genetixbay.com/knowledge/glossary/sib-cross.md)), and so on. In cannabis "F2" usually means sibling-crossed F1s, not selfed. |
| **BX1, BX2 (BC1, BC2)** | Backcross generations: offspring crossed back to one parent. |
| **S1** | Seed from a plant pollinated by itself (selfed), usually by reversing one branch or a clone. |
| **IBL** | Inbred line: a population inbred over several generations until it breeds fairly true. No fixed generation count defines it; treat the label as a claim. |
| **Polyhybrid** | A line with many ancestors from different gene pools, typical of modern "strains". |
| **Landrace** | A locally adapted, farmer-maintained population with a distinct identity and history in a region [5]. |
| **Clone-only (cut)** | A selected individual kept only as clones; the name refers to one genotype. |
| **Tester / test grow** | Seed sent to growers to report how a line performs. |
| **[Feminised seed](https://genetixbay.com/knowledge/glossary/feminised-seed.md)** | Seed made with pollen from a sex-reversed female; nearly all progeny female. |
| **Regular seed** | Seed from a true male x female; about half males. |

## Naming and records

| Term | Meaning |
|---|---|
| **Cultivar** | A plant population selected for distinct, uniform and stable traits, formally named under the ICNCP [4]. Most cannabis "strains" are not formal cultivars. |
| **Strain** | The popular word for a named cannabis line. Not a botanical rank; the same name can hide different genetics. |
| **Accession** | A sample entered in a collection (seed bank, genebank) with an ID. |
| **GB-ID** | GenetixBay's permanent identifier for lines, batches, plants and documents. See [documenting lineage evidence](https://genetixbay.com/knowledge/breeding/documenting-lineage-evidence.md). |
| **[Evidence levels L0-L4](https://genetixbay.com/knowledge/glossary/evidence-levels-l0-l4.md)** | How well a lineage claim is supported: unverified, community reported, breeder reported, documented, lab-confirmed. |

## Evidence ladder used in GenetixBay articles

*Established* (multiple studies or extension consensus), *Supported* (some research or strong grower consensus), *Grower practice* (widely used, little research), *Contested*, *Myth*.

## Sources

1. Suza W, Lamkey K (eds). 2023. Quantitative Genetics for Plant Breeding. Iowa State University Digital Press. https://iastate.pressbooks.pub/quantitativegenetics/
2. Miko I. 2008. Gregor Mendel and the principles of inheritance. Nature Education 1(1):134. https://www.nature.com/scitable/topicpage/gregor-mendel-and-the-principles-of-inheritance-593/
3. Hillig KW, Mahlberg PG. 2004. A chemotaxonomic analysis of cannabinoid variation in Cannabis (Cannabaceae). American Journal of Botany 91(6):966-975. https://doi.org/10.3732/ajb.91.6.966
4. Brickell CD, et al. (eds). 2016. International Code of Nomenclature for Cultivated Plants, 9th edition. Scripta Horticulturae 18. ISHS. https://www.ishs.org/scripta-horticulturae/international-code-nomenclature-cultivated-plants-ninth-edition
5. Villa TCC, Maxted N, Scholten M, Ford-Lloyd B. 2005. Defining and identifying crop landraces. Plant Genetic Resources 3(3):373-384. https://doi.org/10.1079/PGR200591