The origins and dispersals of agricultural products have long been of great interest to scholars from a number of different disciplines, not least of which is archaeology. This profound transition in human lifeways from hunting and gathering to settled agriculture, occurred independently in at least seven to eight regions of the world during prehistory: namely, the eastern United States, Mesoamerica, South America, the Near East, China, New Guinea, probably mainland southeast Asia, and possibly India (see Barker 2006; Kennett and Winterhalder 2006; Zeder et al. 2006; Cohen 2009; and Price and Bar-Yosef 2011 for recent updates of the evidence). During the past ten to fifteen years, an enormous amount of new information has been published documenting the transition from foraging to food production in archaeological records worldwide. Moreover, a steady stream of paleoecological and molecular research has provided increasingly detailed information on the ecological contexts of food production origins, associated human modification of environments, ancestry of crop plants, and geography of agricultural origins (see Piperno 2006a, 2011, and in press for recent reviews of archaeological, paleoecological, and molecular data for Mesoamerica and Central and South America; see Smith 2006 for data for North America).

Mexico, along with the remainder of Mesoamerica in smaller part, formed one of the world’s great centers for the independent development of agriculture. Dozens of crop plants were brought under cultivation and domesticated there in the prehistoric era. They include the most famous crop of the Americas, maize (Zea mays); two species of squash (Cucurbita pepo and C. argyrosperma); the common bean and small-seeded (sieva) lima bean (Phaseolus vulgaris and P. lunatus [sieva type]); the pseudocereals Amaranthus and Chenopodium; avocados (Persea americana); at least one species of chile pepper (Capsicum annuum); and a number of important tree crops, including Leucaena spp. (the guajes) and Spondias purpurea (the hog plum). Two other premier plants, tomato (Lycopersicum esculenta) and cacao, or chocolate (Theobroma cacao), were native to South America but were probably domesticated in Mexico, based on current archaeological data and on the locations at which they were being cultivated when Europeans arrived. The early history of many of these plants is poorly understood and a few have not yet been found or recognized in archaeological records (Table 11.1).

Molecular research indicates that many species, including maize and C. argyrosperma squash, were domesticated once within a circumscribed region. Others, however, have been robustly shown by genetic and molecular data to have been domesticated two or more times either within Mesoamerica or in Mesoamerica, South America, and North America (e.g., Chenopodium, Cucurbita pepo, the common and lima bean, avocado, Spondias purpurea, and the turkey). A few domestications, such as in Leucaena, involved hybridizations between two different species that likely were facilitated by early human management in house gardens.

There is thus an increasingly rich and varied history of plant domestication and agriculture that has and will continue to provide a bounty of information for archaeologists, botanists, molecular biologists, and other scholars to explore. Table 11.1 lists the postulated geographic locales for the origins of Mesoamerican crops based on the present, combined evidence from molecular, archaeological, and botanical research. The table also provides a more complete, though still not exhaustive, list of crops known or thought to have been domesticated in Mesoamerica, along with the ages and areas of their early appearances. Mesoamerica is a region of great physical and ecological diversity; it has major mountain ranges and significant expanses of lowlands, with vegetation ranging from temperate and tropical forests of varying types to cactus/shrublands and deserts (Figure 11.1). Domestication and subsequent agricultural development occurred through a range of these ecological zones (Figure. 11.1; Table 11.1).

It is now clear that in both the highlands and tropical lowlands, plant cultivation and domestication emerged during the early Holocene period. This makes the chronology, if not the cultural and ecological contexts, of agricultural origins in both places similar to that in the Near East and China. It should be pointed out, however, that although our understanding of when and how Mesoamerican food production and agriculture emerged has become more clear recently, the evidence is still derived from relatively few lowland and highland sites, and mostly from cave and rock shelters that were sometimes occupied intermittently or ephemerally during the early and middle Holocene. Consequently, the sites probably provide incomplete information about the plants that were undergoing early cultivation and about the cultivated and domesticated crops that were available to human groups at various time periods for their subsistence economies. Moreover, even dry caves don’t leave perfect records of prehistoric plant subsistence unbiased by preservation and sampling. The following sections discuss the available information in more detail.

Table 11. 1 Cultivated and Domesticated Plants of Mesoamerica

Plant Common Name Date, and Place of earliest Appearance, Probable Place of Domestication

Zea mays Maize 8700 BP, Xihuatoxtla Shelter, Guerrero, Central Balsas region; Central Balsas region of Guerrero/Michoacán

. . .

Setaria macrostachya (D?)* Foxtail millet Between 600 and 4400 BP (?), Ocampo caves, Tamaulipas; highland Mexico

Amaranthus cruentus ?, present in the Tehuacán sequence, chronology needs clarification; highland Mexico

Amaranathus hypochondriacus

. . .

Agave spp. Maguey, century plant ?, it is uncertain if agave remains at Tehuacán were cultivated