One pepper can carry half a dozen identifiers at once. A landrace collected in Hungary might sit in USDA GRIN as a PI number and in the IPK Gatersleben genebank as a CAP number. The Dutch CGN collection gives it a third code, and WikiPepper adds a Universal Pepper Number. None of those systems competes with the others. Each answers a different question, and knowing which is which saves you from chasing the same seed lot in four databases.

The systems at a glance

SystemRun byCode looks likeAnswers
Binomial taxonomyBotanists under the ICNCapsicum baccatum var. pendulumWhat species is this?
USDA GRIN / NPGSUSDA-ARS, Griffin, GeorgiaPI 152452Which seed lot, collected where?
CAP seriesIPK Gatersleben genebank, Germany (DEU146)CAP 0201Which German genebank accession?
CGN seriesCentre for Genetic Resources, WageningenCGN 16836Which Dutch genebank accession?
WorldVegWorld Vegetable Center, TaiwanVI029701Which tropical Asian accession?
Bioversity descriptorsBioversity InternationalTrait codes, not accession numbersHow do we record a trait the same way?
UPNWikiPepper FoundationC-Y-SM-M-7-001What is this pepper, whatever it is called?
PVP and UPOVNational plant variety officesCertificate numbersWho holds legal rights to this cultivar?

Binomial taxonomy, and how many species there are

The International Code of Nomenclature governs Latin names. Barboza and colleagues revised the whole genus in 2022 and recognise 43 species and five varieties, which settled a pile of long-running arguments. Names growers still use casually turn out to be varieties: C. praetermissum ranks as C. baccatum var. praetermissum. Taxonomy handles wild species well and cultivars badly, because a Latin binomial has nowhere to put the difference between the 2,202 C. chinense entries in this database. Our species list from Kew tracks the accepted names.

USDA GRIN

The Germplasm Resources Information Network catalogues the US National Plant Germplasm System. Capsicum lives at the Plant Genetic Resources Conservation Unit in Griffin, Georgia, and each accession carries a Plant Introduction number written as PI plus digits. Passport data covers collection site, donor, year and species determination, and researchers can request seed. GRIN is free, and for anyone hunting a landrace with a documented origin it is the first place to look.

What does a CAP number mean?

CAP is the Capsicum accession series of the genebank at the Leibniz Institute of Plant Genetics and Crop Plant Research in Gatersleben, Germany, which carries FAO institute code DEU146. Genesys shows the chain plainly: accession CAP 1096, Capsicum annuum, held by DEU146. Those codes reach hobby growers through seed swaps, which is why a variety list can suddenly sprout numbers like CAP 1445 with no explanation attached.

Plenty of sources, this site's own pages among them, used to credit CAP numbers to the Chile Pepper Institute at New Mexico State University. That attribution is wrong. The Chile Pepper Institute is a research and education body founded in 1992, and it releases the NuMex cultivar line and sells seed. It publishes no accession prefix of its own. If you read CAP in a paper or on a seed packet, look to Gatersleben.

European and international collections

The Centre for Genetic Resources in Wageningen holds the Dutch national collection, roughly 24,700 accessions across all crops, with Capsicum passport and trait data standardised for cross-database work. The World Vegetable Center in Taiwan, set up in 1971 as AVRDC, holds about 8,165 Capsicum accessions, the largest single-institution collection anywhere and near 11 percent of the world total. WorldVeg numbers its accessions with a VI prefix. EMBRAPA in Brazil concentrates on South American material, strong in baccatum and chinense diversity with ethnobotanical notes attached. INRAE in France works pepper alongside the rest of the Solanaceae, with a focus on fruit traits and disease resistance.

Descriptor systems

Bioversity International, formerly IPGRI, publishes the descriptor list for Capsicum: a fixed vocabulary for flower position, leaf shape, fruit colour at each stage, growth habit and pungency. Genebanks worldwide record traits against it, which is the reason two institutions on opposite sides of the planet describe the same accession in the same words. Descriptors are not identifiers. They say what a plant looks like, not which plant it is.

WikiPepper Universal Pepper Nomenclature

A Universal Pepper Number describes the pepper rather than recording who collected it. That fills the gap the genebanks leave, because the thousands of cultivars and crosses moving through the hobby trade will never get an accession number. Trade names drift. The code stays put.

A UPN reads S-C-P-F-T-###: species, ripe colour, pattern and skin, pod form, heat, serial. Scotch Bonnet carries C-Y-SM-M-7-001, meaning C. chinense, ripens yellow, smooth skin, bonnet form, heat 7, first serial in that description. Two ripe colours put both letters in alphabetical order. Pattern codes are two letters each, run together alphabetically, and a plain smooth pod gets SM. A pepper takes one pod form, the shape it usually sells as. The heat digit runs 0 to 9 and comes from the top of the SHU range, so a pepper rated 2,500 to 8,000 SHU is a 4 rather than a 3. An interspecific cross shows both species letters, as in A×C.

The WikiPepper Foundation issues every code from one ledger, and a serial never gets reused even after its code retires. The board looks for a line grown eight years or more, past F8 and true from seed. That is guidance rather than a gate: newer lines can hold a provisional code if the applicant shows what makes them distinct. No pepper gets a code until its entry carries a species, a ripe colour, a pod form and an SHU range. Spec 1.0 governs the current codes.

Which system should I use to identify a pepper?

It depends on what you are doing. Reproducing a published study means chasing the accession number the authors used, since that points at a specific seed lot. Sourcing rare germplasm means GRIN, CGN, IPK or WorldVeg, whichever holds it. Sorting out which of the six things called Purple Tiger you actually bought means the UPN, because that code describes traits rather than provenance. Publishing a species claim means the Latin name from the current monograph.

No single database covers everything, so serious identification work crosses two or three. Our taxonomy guide handles the botany, and species, landraces and cultivars covers the vocabulary underneath all of it.

Vendor and hobbyist codes

Seed vendors run their own shorthand, and it never travels well. Breeders label generations as F2 or F3, tag traits like variegation or dwarf habit, and assign internal cross numbers that mean nothing off their own catalogue. Treat a vendor code as a pointer back to that vendor, never as a stable identifier. When two sellers list the same code for different plants, and they do, only the pod in front of you settles it. Browse the full database when you need to match a name to a described pepper.

Sources & Further Reading