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All crops are the product of a domestication process that started less than 12,000 years ago from one or more wild populations1,2. Farmers selected desirable phenotypic traits (such as improved energy accumulation, palatability of seeds and reduced natural shattering3) while leading domesticated populations through several more or less gradual demographic contractions2,4. As a consequence, the erosion of wild genetic variation5 is typical of modern cultivars, making them highly susceptible to pathogens, pests and environmental change6,7. The loss of genetic diversity hampers further crop improvement programmes to increase food production in a changing world, posing serious threats to food security8,9. Using both ancient and modern seeds, we analysed the temporal dynamics of genetic variation and selection during the domestication process of the common bean (Phaseolus vulgaris) in the southern Andes. Here, we show that most domestic traits were selected for before 2,500 years ago, with no or only minor loss of whole-genome heterozygosity. In fact, most of the changes at coding genes and linked regions that differentiate wild and domestic genomes are already present in the ancient genomes analysed here, and all ancient domestic genomes dated between 600 and 2,500 years ago are highly variable (at least as variable as modern genomes from the wild). Single seeds from modern cultivars show reduced variation when compared with ancient seeds, indicating that intensive selection within cultivars in the past few centuries probably partitioned ancestral variation within different genetically homogenous cultivars. When cultivars from different Andean regions are pooled, the genomic variation of the pool is higher than that observed in the pool of ancient seeds from north and central western Argentina. Considering that most desirable phenotypic traits are probably controlled by multiple polymorphic genes10, a plausible explanation of this decoupling of selection and genetic erosion is that early farmers applied a relatively weak selection pressure2 by using many phenotypically similar but genetically diverse individuals as parents. Our results imply that selection strategies during the past few centuries, as compared with earlier times, more intensively reduced genetic variation within cultivars and produced further improvements by focusing on a few plants carrying the traits of interest, at the cost of marked genetic erosion within Andean landraces.

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The archaeological record shows that large pre-Inca agricultural systems supported settlements for centuries around the ravines and oases of northern Chile's hyperarid Atacama Desert. This raises questions about how such productivity was achieved and sustained, and its social implications. Using isotopic data of well-preserved ancient plant remains from Atacama sites, we show a dramatic increase in crop nitrogen isotope values (δ15N) from around AD 1000. Maize was most affected, with δ15N values as high as +30‰, and human bone collagen following a similar trend; moreover, their carbon isotope values (δ13C) indicate a considerable increase in the consumption of maize at the same time. We attribute the shift to extremely high δ15N values-the highest in the world for archaeological plants-to the use of seabird guano to fertilize crops. Guano-'white gold' as it came to be called-thus sustained agricultural intensification, supporting a substantial population in an otherwise extreme environment.

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We assess diet and economies of middle Holocene (∼7,500 to 4,000 calibrated [cal] B.P.) humans at coexisting mound sites (Huaca Prieta and Paredones) in north coastal Peru and document regular consumption of maize by ∼6,500 to 6,000 cal B.P. and its earliest use as a staple food in this area of the Andes between 5,000 and 4,500 cal B.P. Stable isotope data from enamel carbonates and dentin collagen (childhood diet) and dental microwear texture analysis (adult diet) demonstrate dietary and economic specialization. Previous studies revealed maize and mixed-food refuse at both sites, but this study documents actual food consumption, showing that these communities situated a few hundred meters apart had significantly distinct diets in childhood and adulthood. Huaca Prieta focused on marine resources, although there are some contributions from terrestrial meat. Paredones individuals primarily consumed maize during childhood (up to 70% of the juvenile diet), as shown by δ13C values, apatite-collagen spacing, and discriminant analysis of δ13Ccoll, δ13Ccarb, and δ15N values. Maize was likely used as a weaning food (e.g., gruel and/or chicha-a maize beverage), hinting at the significant role of breastfeeding mothers, weanling infants, and children in the development of maize as a staple crop. Additionally, dental microwear data show Paredones adult diets are high in abrasives, potentially from maize processing. The distinct foodways at these neighboring sites result from and also reflect their social and political distinctions. These differences in food production, distribution, and consumption generated opportunities for exchange, an interaction that bound them together in mutual benefit.

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The onset of plant cultivation is one of the most important cultural transitions in human history1-4. Southwestern Amazonia has previously been proposed as an early centre of plant domestication, on the basis of molecular markers that show genetic similarities between domesticated plants and wild relatives4-6. However, the nature of the early human occupation of southwestern Amazonia, and the history of plant cultivation in this region, are poorly understood. Here we document the cultivation of squash (Cucurbita sp.) at about 10,250 calibrated years before present (cal. yr BP), manioc (Manihot sp.) at about 10,350 cal. yr BP and maize (Zea mays) at about 6,850 cal. yr BP, in the Llanos de Moxos (Bolivia). We show that, starting at around 10,850 cal. yr BP, inhabitants of this region began to create a landscape that ultimately comprised approximately 4,700 artificial forest islands within a treeless, seasonally flooded savannah. Our results confirm that the Llanos de Moxos is a hotspot for early plant cultivation and demonstrate that-ever since their arrival in Amazonia-humans have markedly altered the landscape, with lasting repercussions for habitat heterogeneity and species conservation.

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Southwestern Amazonia is considered an early centre of plant domestication in the New World, but most of the evidence for this hypothesis comes from genetic data since systematic archaeological fieldwork in the area is recent. This paper provides first-hand archaeobotanical evidence of food production from early and middle Holocene (ca. 9,000-5000 cal. BP) deposits at Teotonio, an open-air site located on a 40 m-high bluff on the south bank of the Madeira river. Such evidence includes the presence of local and exotic domesticates such as manioc (Manihot esculenta), squash (Cucurbita sp.) and beans (Phaseolus sp.), alongside edible fruits such as pequiá (Caryocar sp.) and guava (Psidium sp.) that point to the beginnings of landscape domestication. The results contribute to an ever-growing number of studies that posit southwest Amazonia as an important centre for early crop domestication and experimentation, and which highlight the longue-durée of human impacts on tropical forest biodiversity around the world.

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Archaeological research suggests significant human occupation in the arid Andean highlands during the 13th to 15th centuries, whereas paleoclimatic studies reveal prolonged drier and colder conditions during that period. Which subsistence strategy supported local societies in this harsh environment? Our field and aerial surveys of archaeological dwelling sites, granaries, and croplands provide the first evidence of extended pre-Hispanic agriculture supporting dense human populations in the arid Andes of Bolivia. This unique agricultural system associated with quinoa cultivation was unirrigated, consisting of simple yet extensive landscape modifications. It relied on highly specific environmental knowledge and a set of water-saving practices, including microterracing and biennial fallowing. This intense agricultural activity developed during a period of unfavorable climatic change on a regional and global scale, illustrative of efficient adaptive strategies to cope with this climatic change.

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Archaeological and palaeoecological studies throughout the Americas have documented widespread landscape and environmental transformation during the pre-Columbian era. The highly dynamic Formative (or Neolithic) period in northern Chile (ca. 3700-1550 yr BP) brought about the local establishment of agriculture, introduction of new crops (maize, quinoa, manioc, beans, etc.) along with a major population increase, new emergent villages and technological innovations. Even trees such as the Algarrobos (Prosopis section Algarobia) may have been part of this transformation. Here, we provide evidence that these species were not native to the Atacama Desert of Chile (18-27°S), appearing only in the late Holocene and most likely due to human actions. We assembled a database composed of 41 taxon specific AMS radiocarbon dates from archaeobotanical and palaeoecological records (rodent middens, leaf litter deposits), as well an extensive bibliographical review comprising archaeobotanical, paleoecological, phylogenetic and taxonomic data to evaluate the chronology of introduction and dispersal of these trees. Although Algarrobos could have appeared as early as 4200 yr BP in northernmost Chile, they only became common throughout the Atacama over a thousand years later, during and after the Formative period. Cultural and natural factors likely contributed to its spread and consolidation as a major silvicultural resource.

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Lycopersicon esculentum known as tomato, although has an Andean origin is a contribution of Mexico to the world is, being the first agricultural product to be exported. This research aimed to review the literature in relation to the origin and evolution of the production of tomato in Mexico within the historical development of the country. In ancient times, the tomato was cultivated in milpas (open field) and chinampas (artificial islands for riparian agriculture) using sustainable methods. Spanish colonizers showed the tomato to the rest of the world and diversified its uses. In independent Mexico, haciendas and railroads integrated the different farming regions. Production decreased during the Mexican revolution, and with land reform, the milpa returned. During the Green Revolution (1970), Sinaloa stood out, with the separation of two systems, subsistence, and modern with technology programs. Biotechnological development (1990) emerged parallel to organic production. So actually with this system, we could return to more sustainable pre-Hispanic ecological principles with less environmental impact.

Lycopersicon esculentum conhecido como tomate, uma contribuição do México para o mundo a partir de sua domesticação, embora sua origem seja andina, é o primeiro produto de exportação agrícola. Esta pesquisa tem como objetivo realizar uma revisão da literatura em relação à origem e evolução da produção de tomate no México e, no desenvolvimento histórico do país. Nos tempos antigos, o tomate foi cultivado em milpas (campo aberto) e chinampas (ilhas artificiais para a agricultura ribeirinha), utilizando métodos sustentáveis. Colonizadores espanhóis introduziram o tomate no restante do mundo, diversificando seus usos. No México independente, fazendas e estradas de ferro integram as diferentes regiões agrícolas. A produção diminuiu durante a revolução mexicana, e com a reforma agrária ocorreu o retorno da milpa. Sinaloa destacou-se durante a Revolução Verde (1970), com a separação dos dois sistemas de subsistência e moderno e, com programas de tecnologia. O desenvolvimento biotecnológico (1990) surge em paralelo à produção biológica. Dada a complexidade do panorama dos alimentos, atualmente, com estes sistemas, podem-se retomar os princípios ecológicos pré-hispânicos mais sustentáveis, com menor impacto ambiental.

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Lycopersicon esculentum known as tomato, although has an Andean origin is a contribution of Mexico to the world is, being the first agricultural product to be exported. This research aimed to review the literature in relation to the origin and evolution of the production of tomato in Mexico within the historical development of the country. In ancient times, the tomato was cultivated in milpas (open field) and chinampas (artificial islands for riparian agriculture) using sustainable methods. Spanish colonizers showed the tomato to the rest of the world and diversified its uses. In independent Mexico, haciendas and railroads integrated the different farming regions. Production decreased during the Mexican revolution, and with land reform, the milpa returned. During the Green Revolution (1970), Sinaloa stood out, with the separation of two systems, subsistence, and modern with technology programs. Biotechnological development (1990) emerged parallel to organic production. So actually with this system, we could return to more sustainable pre-Hispanic ecological principles with less environmental impact. (AU)

Lycopersicon esculentum conhecido como tomate, uma contribuição do México para o mundo a partir de sua domesticação, embora sua origem seja andina, é o primeiro produto de exportação agrícola. Esta pesquisa tem como objetivo realizar uma revisão da literatura em relação à origem e evolução da produção de tomate no México e, no desenvolvimento histórico do país. Nos tempos antigos, o tomate foi cultivado em milpas (campo aberto) e chinampas (ilhas artificiais para a agricultura ribeirinha), utilizando métodos sustentáveis. Colonizadores espanhóis introduziram o tomate no restante do mundo, diversificando seus usos. No México independente, fazendas e estradas de ferro integram as diferentes regiões agrícolas. A produção diminuiu durante a revolução mexicana, e com a reforma agrária ocorreu o retorno da milpa. Sinaloa destacou-se durante a Revolução Verde (1970), com a separação dos dois sistemas de subsistência e moderno e, com programas de tecnologia. O desenvolvimento biotecnológico (1990) surge em paralelo à produção biológica. Dada a complexidade do panorama dos alimentos, atualmente, com estes sistemas, podem-se retomar os princípios ecológicos pré-hispânicos mais sustentáveis, com menor impacto ambiental. (AU)

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The data presented in this paper provide direct microbotanical evidence concerning the early use of potato (Solanum tuberosum) within its botanical locus of origin in the high south-central Andes. The data derive from Jiskairumoko, an early village site in the western Titicaca Basin dating to the Late Archaic to Early Formative periods (∼3,400 cal y BC to 1,600 cal y BC). Because the site reflects the transition to sedentism and food production, these data may relate to potato domestication and early cultivation. Of 141 starch microremains recovered from 14 groundstone tools from Jiskairumoko, 50 are identified as consistent with cultivated or domesticated potato, based on reference to published materials and a study of wild and cultivated potato starch morphology. Along with macro- and microbotanical evidence for chenopod consumption and grinding tool data reflecting intensive use of this technology throughout site occupation, the microbotanical data reported here suggest the intensive exploitation, if not cultivation, of plant resources at Jiskairumoko. Elucidating the details of the trajectory of potato domestication is necessary for an overall understanding of the development of highland Andean agriculture, as this crop is central to the autochthonous agricultural suite. A paucity of direct botanical evidence, however, has hindered research efforts. The results of the modern and archaeological starch analyses presented here underscore the utility of this method in addressing questions related to the timing, mode, and context of potato origins.

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