Maní: a crop domesticated in southeastern Bolivia, listed as mission food in 1786, and now grown on 28 million hectares
The peanut is an American domesticate the Spanish world moved rather than made. Genetics and biogeography place its origin in southeastern Bolivia, where both wild progenitors still grow near Villa Montes, and its main landraces had spread across South America before 1492; Peruvian archaeology carries its use back thousands of years. Alcedo's dictionary of 1786 lists maní among the ordinary foods of the Apolobamba missions, beside American yuca and maize and Old World rice.
Why this wins its question: Popular accounts of the peanut open with "native to South America" and then jump to George Washington Carver, and the Spanish-language colonial record for the crop is almost never quoted at all. This object gives the origin at the resolution the genetics actually supports — southeastern Bolivia, both wild progenitors still growing near Villa Montes in Tarija, a single-plant bottleneck, the main landraces already regionally distributed before 1492 — and pairs it with a dated colonial page: Alcedo in 1786 listing maní among the common foods of the Apolobamba missions beside yuca, maize, camote, cotton, coca and Old World rice, which is what the Columbian exchange looked like from inside a mission town rather than from a map of arrows. It then does what the popular accounts never do: it names the disagreement between its own two scientific sources over when domestication happened, and says which question it cannot answer with what was read.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
Alcedo's Diccionario geográfico-histórico de las Indias Occidentales (Madrid, 1786) shows the crop inside a Spanish colonial jurisdiction as an everyday food rather than a curiosity. Describing the eight Franciscan mission towns of Apolobamba, in the Andean foothills of upper Peru, he writes that the peoples there speak several languages, being of different nations mixed together, and that "los frutos que cultivan son yucas, arroz, maiz, camotes, mani y plátanos, que son los alimentos comunes á todos los Pueblos: tambien cultivan algodon, de que texen camisetas para hombres y mugeres, cogen alguna cera, que labran las abejas en los troncos de los árboles, coca, y en los pampas ó llanos de Isllamas, algun cacao" (tomo I, p. 131). The list runs the exchange in both directions in a single line: American yuca, maize, camote, maní, cotton, coca and cacao alongside Old World rice and the plantain.
Cultivated peanut, Arachis hypogaea, "was domesticated in central South America by early agriculturalists, following tetraploidization of a hybrid involving the merger of two progenitor diploid species: A. duranensis and A. ipaënsis". The 2020 genotypic study of the United States peanut core collection concludes that "the genetics, phenotypic characteristics, and biogeography are all consistent with previous reports of tetraploid peanut originating in Southeast Bolivia", and notes as one line of evidence that both ancestral diploids "are found close to Villa Montes, in the Province of Tarija".
The same study describes the origin as a severe bottleneck: the crop's diversity "appears to have arisen quickly, from a severe genetic bottleneck at the time of the tetraploidization event roughly 10,000 years ago, likely involving a rare, single plant in an early horticulturalist's garden". That is the cost written into the crop itself — a world oilseed descended from one hybrid plant, with the narrow diversity such an origin implies, which is why the collection being genotyped exists at all.
A 2017 review of wild grain-legume germplasm places the centre of origin of the genus in South America, "with wild species found in Bolivia, Brazil, Paraguay, Argentina and Uruguay", and gives the archaeological record: "the oldest archaeological records of A. hypogaea came from Huarmey Valley, Peru, dating from approximately 3500–4500 years ago", while records of peanut use at Ñanchoc Valley in northern Peru about 7,840 years ago "may correspond to the use of wild species or the very early stage of domestication". It also reports evidence that the plant could have originated in northern Argentina and eastern Bolivia, and that the tetraploid wild ancestor is taken to be A. monticola.
The two sources read here do not date the same event the same way, and the object does not adjudicate between them. The 2020 study puts the tetraploidisation at roughly ten thousand years ago; the 2017 review reports a hybridisation and genome duplication some three and a half thousand years ago and archaeological peanut from three and a half to four and a half thousand years ago. The disagreement is real, it turns on whether molecular-clock estimates or dated remains are taken as the anchor, and any figure quoted for "when the peanut was domesticated" should be attributed to one method rather than repeated as settled.
What the colonial centuries added was distribution, not domestication. The 2020 study finds the main botanical varieties already regionally distributed across South America before contact — the earliest landraces associated with accessions from Bolivia, Peru and Ecuador — and then states plainly that "throughout the colonial period (∼1492–1832), peanut cultivation spread quickly around the world", with "little genetic clustering by country of origin, reflecting peanut's rapid global dispersion in the 18th and 19th centuries". The crop the world grows was shaped by American farmers; Iberian and later shipping moved it.
The scale of what moved is worth stating in the units the agronomists use: in 2017, twenty-eight million hectares worldwide produced forty-seven million metric tons, and peanut "is now an important source of protein and oil worldwide". An oilseed of that weight in world food supply is a domesticate of the southern Andean foothills, and the populations that made it left no written record of doing so.
Two limits are stated rather than left implicit. First, only one colonial-era Spanish witness was opened for this object — Alcedo's 1786 dictionary — so nothing here should be read as a claim about which European author first described the plant in print, a question the sixteenth-century chroniclers would settle and none of them was read here. Second, Alcedo's entry is a compilation made in Madrid from other men's relaciones, which is why its claim carries the lower confidence of the set rather than the confidence a first-hand observation would take.