Six words do most of the damage in pepper catalogs: species, variety, cultivar, landrace, hybrid and accession. They are not interchangeable, and the difference decides whether your saved seed comes back true. A species is a biological unit. A cultivar is a human selection with a stable name. A landrace is a diverse local population. An accession is a numbered sample in a genebank. Everything below sorts out the rest.

Species

Kew's Plants of the World Online currently accepts 43 species in Capsicum. Five of them carry the crop: C. annuum, C. chinense, C. baccatum, C. frutescens and C. pubescens. The other 38 are wild, and the count moves as taxonomists split and merge. Two names that circulate in grower charts are no longer good: C. praetermissum is a synonym of C. rabenii, and C. anomalum sits in a different genus entirely as Tubocapsicum anomalum. Our Kew species list tracks the accepted set.

Species boundaries in Capsicum rest on crossing behavior, chromosome complements and evolutionary history rather than on pod shape. The five domesticates do not freely interbreed, though determined breeders force several of the combinations.

Subspecies and botanical varieties

These are nature's subdivisions inside a species, produced by geographic or ecological isolation, and they breed true. C. annuum var. glabriusculum is the standing example: the wild chiltepin from which every domesticated annuum descends. Botanical varieties travel in italics after the abbreviation var., which keeps them visually distinct from cultivated varieties. Chiltepin carries that varietal name in our database.

Cultivars

A cultivar is a cultivated variety: a human selection, genetically stable enough to reproduce its traits, and named under the International Code of Nomenclature for Cultivated Plants. The Code sets the typography, and it is worth following. Cultivar epithets go in single quotation marks and stay upright, never italic: Capsicum chinense 'Trinidad Moruga Scorpion'. The epithet runs no more than 30 characters and 10 syllables. Trade designations, the marketing names printed on a rack packet, must look typographically different from the real cultivar name, which is why the same plant can reach you under two labels.

Landraces

A landrace is a locally adapted population maintained by traditional seed saving, genetically diverse on purpose. Mexico's chile de arbol populations qualify. So do the pequin stands of Texas, the aji varieties of Peru, and Criollo de Morelos 334, the Mexican landrace whose Phytophthora resistance now underpins commercial rootstocks. Plant a landrace and you get variation in pod shape, maturity and heat. That heterogeneity is the point: it is the population's insurance against a bad year, and it is exactly what a breeder strips out to make a cultivar.

What is an accession number, and who issues it?

An accession is one documented sample of plant material held in a genebank, tied to passport data recording where it came from, who collected it and when. The prefix names the holder.

PI numbers come from the USDA National Plant Germplasm System, searchable through GRIN. They are permanent and unambiguous, which is more than the common name manages: PI 257068 and PI 260535 both travel under the name Aji Picante, and they are not the same plant. CGN numbers come from the Centre for Genetic Resources in the Netherlands. CAP numbers come from the genebank at the Leibniz Institute of Plant Genetics and Crop Plant Research in Gatersleben, Germany, institute code DEU146. Several of them circulate in the hobby seed trade as variety names in their own right, including CAP 1445. An older version of this page, and the site glossary, credited CAP numbers to the Chile Pepper Institute at New Mexico State University. Genesys and IPK's own records place them at Gatersleben.

Hybrids, crosses and what breeds true

An F1 hybrid is the first generation from two distinct stable parents. It gives uniformity and hybrid vigor, and it does not come true from saved seed. 'Mama Mia Giallo', the 2014 All-America Selections sweet pepper, is a straightforward commercial F1. 'Jaloro' is not, despite years of lists calling it one: Ben Villalon and colleagues released it through Texas A&M in 1992 as an open-pollinated multiple-virus-resistant yellow jalapeno, and Jaloro seed comes true. Save from an F1 instead and the F2 generation segregates across every parental combination, which is a breeding project rather than a mistake.

A cross is any deliberate mating, inside a species or between two. Bosland and Baral tested Bhut Jolokia in 2007 and described it as a putative naturally occurring interspecific hybrid, mostly C. chinense with C. frutescens in the background. That finding gets stretched into a claim that most superhots are chinense by frutescens crosses, and the evidence does not go that far. Stabilizing a cross takes selection through F3, F4 and beyond, usually reaching a line that breeds true around F7 or F8. Our breeding guide walks that through, and isolation versus open pollination covers keeping your seed clean while you do it.

How do the terms fit together in practice?

Take C. chinense as the species. Scotch Bonnet is a Jamaican landrace inside it, diverse enough that four growers will show you four pod shapes. Scotch Bonnet MOA, selected through Jamaica's Ministry of Agriculture, is a cultivar pulled out of that landrace. Red Savina came the same way, as Frank Garcia's selection out of habanero. It held the Guinness record at 577,000 SHU from 1994 until February 2007, when Bhut Jolokia took the title. A genebank sample of any of them becomes an accession with a number. Cross one to a Carolina Reaper and you have an F1 that belongs to nobody's cultivar list until someone stabilizes it.

The terms side by side

Term.Kind of category.Who makes it.Breeds true?Example.
Species.Biological.Evolution.Yes.C. baccatum.
Botanical variety.Biological.Evolution.Yes.C. annuum var. glabriusculum.
Landrace.Cultural.Traditional farmers.To type, with wide variation.Criollo de Morelos 334.
Cultivar.Horticultural.Breeders and selectors.Yes, if open-pollinated.'Jaloro'.
Heirloom.Horticultural.Generations of savers.Yes.'Fish'.
Open-pollinated.Reproductive status.Insects and the grower.Yes, with isolation.'California Wonder'.
F1 hybrid.Horticultural.Breeders.No; F2 segregates.'Mama Mia Giallo'.
Cross.Breeding event.Breeders, or insects.Not yet.Lemon Drop by Reaper.
Breeding line.Breeding stage.Breeders.Partly, by F5.An unnamed F5 selection.
Selection.Breeding event.One grower, one plant.Depends on the parent.Red Savina out of habanero.
Strain.Informal.Growers.Sometimes.Scotch Bonnet MOA Yellow.
Accession.Conservation record.Genebanks.Not applicable; it is a sample.CAP 1445; PI 257068.

What this means when you buy seed

Ask which category the listing belongs to before you plan around it. F1 seed is worth buying and not worth saving unless you want the project. Landrace seed will vary, so grow several plants and select. An accession number on a packet is the most reliable identity in the trade, because the number outranks the name. Every record on this site also carries a Universal Pepper Number encoding species, color, pattern, form and heat, which settles most naming arguments faster than a catalog description. The site glossary defines the rest of the vocabulary.

Sources & Further Reading