The most important lowland roots and tubers are achira (Canna edulis), lleren (Calathea allouia), arrowroot (Maranta arundinacea), manioc (Manihot esculenta), and sweet potato (Ipomoea batatas). Except for manioc, evidence for the origins of root and tuber crops is largely lacking. It is likely that all were domesticated in the seasonally dry, low to midelevation tropics; formation of subterranean storage organs is a seasonality adaptation. Suitable environments are found east of the Andes to the north and south of the Amazon, on the Ecuadorian coast, and in parts of Central America.
Handbook of South American Archaeology, edited by Helaine Silverman and William H. Isbell.
Springer, New York, 2008
Figure 7.1. Areas of origin of domesticated plants. (Adapted from Piperno and Pearsall 1998: figs. 3.18, 3.19) (Drawn by Kristin Smart)
Productive and undemanding, manioc produces more carbohydrates per edible portion than other lowland root/tubers. While “bitter” varieties must be processed to remove toxic cyanogenic glycosides, “sweet” varieties can simply be boiled or roasted. Research suggests an origin either in seasonal forests of inland Guianas/Venezuela or the cerrados of central Brazil. Olsen and Schaal (1999) argue that manioc was domesticated from M. esculenta subsp. flabellifolia on the southern border of the Amazon basin. Wild populations occur today in forest patches in west-central Brazil and eastern Peru. There are significant genetic differences between bitter and sweet landraces; each likely evolved separately after domestication (Elias et al. 2004). Perry’s (2002) research into size and morphology of manioc starch suggests that coastal Peruvian and lowland Neotropical types have been separated for several millennia.
Mid - and High Elevation Roots and Tubers
Mid - and high elevation roots and tubers include potato (Solanum tuberosum), oca (Oxalis tuberosa), mashwa (Tropaelum tuberosum), ullucu (Ullucus tuberosus), and jicama (Pachyrrhizus ahipa). Except for potato, little is known of the ancestry of mid - and high elevation root/tuber crops. Oca and mashwa, with potato, were likely domesticated in central Peru to northern Bolivia. DNA analysis of the Oxalis tuberosa alliance, species related to oca, supports an origin in southern Peru and northwestern Bolivia (Emshwiller 2002).
At the time of Spanish contact, traditional tetraploid potatoes, Solanum tuberosum subsp. andigena, were grown throughout the Andes, from 2,000-4,000 masl (Hawkes 1990). Greatest diversity lies in the central Andes, and the primitive diploid domesticate, Solanum stenotomum, is grown from central Peru to central Bolivia. Northern Bolivia is home to S. leptophyes, a related wild diploid, leading Hawkes (1990) to propose the southern Lake Titicaca basin as the area of origin of S. stenotomum. Other researchers think it impossible to establish which wild diploid in the brevicaule-complex is ancestral (Van Den Berg et al. 1996), making it difficult to narrow the range.
Pseudocereals
Here I consider quinoa (Chenopodium quinoa), canahua (C. pallidicaule), and amaranth (Amaranthus caudatus). Quinoa, canahua, and amaranth were traditionally cultivated in high elevation, semi-arid regions with potato, other Andean tubers, and tarwi (lupine). Domesticated quinoa is tetraploid, and probably originated from a wild tetraploid. C. hircinum, occurring today in lowland Argentina, is one possible ancestor, but the highlands of southern Peru and Boliva are a more likely domestication center. Canahua may have originated as a grain and forage crop of extreme elevations. Andean amaranth is closely related to Mexican domesticated amaranth, A. cruentis, and may have emerged from it. However, A. hybridus, the progenitor of Mexican amaranth, has a widespread range that includes the Andes. Andean amaranth is grown in temperate valleys of Peru, Bolivia, and northwestern Argentina.
Maize
Maize (Zea mays) was widespread in the Andes at contact and adapted to a broad range of habitats. DNA studies indicate that wild Zea mays subsp. parviglumis, Balsas teosinte, gave rise to maize. Balsas teosinte is native to the tropical deciduous forest of southern and western Mexico, precluding an independent South American origin of maize. The maize that spread out of Mexico was primitive, characterized by small cobs and kernels. Maize evolved into a productive crop throughout its range.
Legumes (Pulses)
Legumes include peanut (Arachis hypogaea), jack bean (Canavalia plagiosperma), common bean (Phaseolus vulgaris), lima bean (Phaseolus lunatus), and lupine (Lupi-nus mutabilis). Pulses are available for every Andean environment. Peanut, adapted to seasonal environments with higher rainfall and dry weather for ripening, was likely domesticated from crosses between wild allotetraploid A. monticola, found from 1,400-2,800 masl in northwestern Argentina, and two wild diploids, A. batizocoi and
An unidentified species from south Bolivia/northwestem Argentina. The ecology of wild species and traditional cultivars suggests ancestral peanuts occupied riverine habitats in open environments.
The ancestry ofjack bean is not well understood. Wild Canavalia species are common along coasts, in secondary vegetation, and along rivers. Domesticated C. plagiosperma is tolerant to drought, salinity, and low-fertility. Coastal South American or lowland Bolivia/ northwest Argentinean origins have been suggested.
Common and lima beans were widely grown at contact in the Andes. Separate species were domesticated in Mesoamerica and South America. Wild common beans in the mid-elevation Andes gave rise to small-seeded (Colombia, Mexico, Central America) and large-seeded (southern Andes) cultivars. Traditional cultivars in northern Peru and Ecuador share traits with both gene pools. Wild lima beans growing in low to mid-elevation from Colombia to Argentina gave rise to large-seeded (western Andes of Ecuador, northern Peru) and small-seeded (Central America/northern South America) cultivars. Multiple domestications and hybridizations are likely.
Lupine is cultivated from 2,000 to 3,850 masl, above the range of Phaseolus. Rich in protein and oil, lupine has a high alkaloid content, and seeds must be processed. Lupine displays wide genetic diversity; it originated from an unknown ancestor in the sierra of Ecuador, Peru, or Bolivia.
Squashes
Three squashes—Cucurbita moschata, Cucurbita maxima and Cucurbita ficifolia—were cultivated for food. The domesticated squashes were derived from separate ancestral species. With wild squashes characterized by bitter flesh, early use focused on seeds and containers. C. moschata is the lowland tropical forest squash. The ancestor is unknown, but related wild species occur in northern Colombia and coastal Panama. C. maxima is cultivated throughout the western Andean slopes. It may be derived from C. andreana, found today in Uruguay and Argentina. C. ficifolia is a high altitude, cool-tolerant species that ranges from Mexico to Bolivia, occurring in the wild in Bolivia.
Gourd
The bottle gourd (Lagenaria siceraria) is an industrial plant. Although ubiquitous in the archaeological record, gourd is not a New World native. Rather, it is believed that African gourds were washed out to sea in the Atlantic and floated to coastal Brazil or northern South America. Bottle gourds can be grown throughout the tropics, subtropics, and into the temperate zone. The flesh is too bitter to eat, but the oily seeds are edible, and gourds make durable containers and floats.
Fibers
Cotton (Gossypium barbadense) was a premier industrial plant. Gossypium species are sun-loving plants adapted to dry conditions. Wild tetraploid species evolved in Pacific coastal Mesoamerica or South America from hybridization between a native diploid and one introduced from Africa or Asia. Wild G. barbadense and G. hirsutum emerged from this tetraploid stock, and were separately domesticated, G. barbadense in northwestern South America west of the Andes, and G. hirsutum in Mexico.
World History
