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Ancient and historic dispersals of sweet potato in Oceania
Abstract
On his voyages across the Pacific, Captain James Cook encountered geographically disparate Polynesian societies, including those living on Easter Island, Hawai’i, and the north island of New Zealand. These far-flung communities cultivated a South American domesticate, the sweet potato (Ipomoea batatas). Subsequent debates concerning the timing and nature of the dispersals of sweet potato into and across the Pacific have proven contentious, including Thor Heyerdahl’s famous Kon Tiki voyage from South America to Easter Island (1). Archaeological research has now conclusively shown that the sweet potato was introduced to Central Polynesia by approximately A.D. 1200 to 1300 (2), most likely by Polynesian voyagers who reached South America and subsequently spread the crop to the widely dispersed islands of the Polynesian triangle (e.g., ref. 3). Now, Roullier et al. (4) use genetic analyses (chloroplast and nuclear microsatellites) of modern and historically collected herbaria samples to clarify longstanding questions concerning historical dispersals of sweet potato across the Pacific. In sum, their research confirms key aspects of the “tripartite hypothesis” for sweet potato dispersal, with major implications beyond Oceania.
... It is grown worldwide with maximum amount of its production coming from countries like China, South Africa, Indonesia, Japan, India, Uganda, and Vietnam (Allemannt et al. 2010;Ayeleso et al. 2016). Ancient sweet potato is grouped into three distinct clusters: Kumara, Camote and Batata (Denham, 2013). These three groups form the two gene pools in the modern sweet potato. ...
... These three groups form the two gene pools in the modern sweet potato. The gene pools are; the Carribean and Central America (Northern) gene pool comprising batata and camote and north-western South American (Southern) gene pool comprising Kumara (Denham, 2013). Batata and Camote also dominate in the New Guinea and Eastern Pacific gene pool. ...
... Thus, since its domestication, sweet potato has been cultivated in two widely separate areas; tropical America and Southwest Pacific (Polynesia). Therefore, sweet potato is believed to have moved from its centre of diversity (America) to caves of Peru then to pacific Polynesia and South East Asia possibly by seafarers before Columbus at around 1200-1300 AD (Denham, 2013). Today sweet potato is cultivated in 117 countries in tropical and subtropics. ...
Sweet potato is considered as one of the major sources of food, animal
feed and industrial raw materials. It is a good source of vitamin C, B2, B6 and
E, as well as dietary fiber, potassium, copper, manganese and iron, and are
low in fat and cholesterol. It is an important root crop in the world and it has
been reported to be drought tolerant. However the crop is sensitive to drought
stress during establishment and storage root initiation periods. Drought at the
storage root initiation stage causes small sized storage root formation thereby
negatively affecting the crop yields. It is considered that drought is one of the
important yield limiting factors which lead to 25 % reduction of sweet potato
yield annually. Drought is associated with undesirable changes at morphological,
physiological, biochemical and molecular levels among genotypes. These changes
are useful indicators in the selection and breeding of drought tolerant genotypes
in sweet potato. Further, breeding of sweet potato for drought-tolerance requires
understanding effects of drought stress, presence of genetic diversity, efficient
crossing and selection methods that lead to identification and development of
potential clonal cultivars.
... At this time, the eastern parts of Remote Polynesia were being colonized. The original sweet potato lineage, called the kumara lineage, is of South American origin, and it thus seems likely that Polynesian voyagers reached the South American coast and subsequently returned to the Pacific islands bringing sweet potato with them, or possibly that South Americans sailed west to the Cook Islands (Clarke et al. 2006: 894;Denham 2013Denham : 1982Gonçalves et al. 2013: 6467;Wallin 2014: 102). Kumara is the word for sweet potato in the regions of Ecuador and Colombia, thus the Polynesian word for sweet potato, kumala and other variants, constitutes linguistic evidence of direct interactions between Polynesians and South Americans (Ioannidis et al. 2020: 575). ...
... The origins of Pacific dogs are ambiguous, and ancient dog remains are rare. In addition, the process of extracting aDNA is very difficult, especially as the warm and humid climate that is prevalent on many Pacific islands is disadvantageous for the preservation of DNA (Denham 2013Greig et al. 2018: 6). Together with the small sample sizes, evidence of dogs in the Pacific before 2000 BP is inconclusive with the exception of the Australian dingo, however there may have been dogs on Papua New Guinea as early as 6000 BP (Matisoo-Smith 2007: 159f). ...
... However, several indications of such a connection have been known in the past. Plants of a known South American origin such as the bottle gourd and sweet potato are acknowledged to have entered Polynesia unaided by the Europeans, although questions remain on the timing and manner of their introduction (Clarke et al. 2006: 894;Storey et al. 2007: 10335;Denham 2013Denham : 1982Gonçalves et al. 2013: 6467;Wallin 2014: 102). According to some studies, ancient chicken from Chile share DNA with ancient Pacific chicken, which taken together with the assumed Polynesian heritage of the Botocudo individuals, the finds of canoes and fishhooks of Polynesian style in California, as well as linguistic similarities between Polynesia and different parts of South America, undoubtedly present strong indications of interactions between Polynesians and South Americans (Storey et al. 2007: 10336;Gonçalves et al. 2013: 6466f). ...
Lumbye, M. 2021. Settlement and interactions in Pacific prehistory: An overview of modern genetic research
The Pacific is the part of the world that was last settled by humans. The colonization occurred in different stages which can be discerned through various methods, one of them DNA analysis of humans as well as other species of animals and plants associated with human settlement. The direction of human migration is traditionally believed to have taken a west-eastern direction, originating in the area near Taiwan and spreading eastward until reaching the islands of Remote Oceania. However, there are also strong indications of an east-western route of interaction, with recent DNA studies confirming prehistoric human contact between South American and Polynesian peoples. The aim of this paper is to investigate the current research on human settlement of the Pacific focusing on the genetic analyses of humans as well as animals and plants believed to have accompanied the human settlers. It is to be hoped that this research survey will shed new light on the subject of geographical origins of Pacific migration and the early interactions and settlement patterns that ensued.
... It was already widely cultivated before Cook's voyages and has been found from archaeological contexts of pre-European age throughout Central and Eastern Polynesia (Hather & Kirch, 1991;Ladefoged et al., 2005;Rosendahl & Yen, 1971). Archaeobotanical finds on New Guinea date to the last few hundred years, suggesting a rapid yet more recent adoption there (Barron et al., 2022;Denham, 2013;Pritchard et al., 2019). ...
Archaeobotanical evidence for the exploitation of vegetatively propagated underground storage organs (USOs) in the tropical regions of Australia, Southeast Asia and the Pacific is currently limited. Although there have been several key studies of archaeological parenchyma published in the past two decades, systematic application of identification methods for vegetatively propagated crop species utilising charred, desiccated or waterlogged remains of parenchymatous tissue is not undertaken on a regular basis. Here, microCT imaging technology is used to compile a three‐dimensional virtual reference collection of parenchymatous tissues for five key USO species known to have been extensively cultivated by people in these regions. The five species are Dioscorea alata , Dioscorea esculenta , Colocasia esculenta , Alocasia macrorrhiza and Ipomoea batatas . These reference samples are used to illustrate the character of the virtual, microCT derived reference collection, and they also capture inter‐species differentiation and intra‐species morphological variation characteristic of many tuberous root crops.
... Sweet potatoes were found on all the outlying islands of the Pacific, including Rapa Nui, Hawaii, and New Zealand (Yen 1974). However, when it was discovered that sweet potato originated in the Americas, its presence in the Pacific led to speculation about how and when it arrived: was its arrival wind-directed, did the seeds float along ocean currents, were they dropped by birds (Bulmer 1966), or were they transported by pre-Columbian transpacific contact with South Americans ( Thor Heyerdahl 1952;Denham 2013)? ...
Rapa Nui is one of the smallest, most remote, and isolated landmasses in the world to have already been settled when European explorers arrived in the eighteenth century. The first people to arrive on Rapa Nui were Polynesians thought to have island-hopped from east Asia (mitochondrial origin in southern China, Ko et al. 2014; Bellwood et al. 2017; language origin in Taiwan, Gray et al. 2009, Klamer 2019; nuclear genome origin in southern China, Yang et al. 2020) over many generations across Oceania to arrive on Rapa Nui approximately 750 years ago (Wilmshurst et al. 2011). The navigational achievements of the Polynesians simply to reach Rapa Nui, let alone persist on it, were extraordinary. Whether or not further eastward exploration included contact with pre-European South America, with accompanying gene flow between the Rapa Nuians and South Americans or only the trade of goods, is still up for debate. Either way, the transportation of animal and plant species undoubtedly proved essential to early Polynesian survival in both Near Oceania (defined as a region of the Pacific that includes New Guinea, the Bismarck archipelago, and the Solomon Islands that was settled 35,000 years ago) and Remote Oceania (defined as the islands east of the Solomon Islands that were settled from 3000 to 3500 years ago).
... For example, the voyaging canoes must have had the capability to hold animals and their food reliably in order to complete the voyages between West and East Polynesia (Anderson, 2009b). 1105 Some have suggested that the sweet potato was transported to the West from South America, which requires considerable seafaring expertise and the ability to undertake two-way voyaging (Denham, 2013). However, a more recent study has provided evidence which suggests that the sweet potato spread to Polynesia by long distance dispersal in pre-human times (Muñoz-Rodríguez et al., 2018). ...
The aim of this thesis is to quantify how Polynesian seafaring technology, climate and season may have influenced the length of the “long pause” between the 35 settlement of West and Central East Polynesia. Current literature has not investigated the performance of Polynesian seafaring technology at the time of the long pause and how this could influence colonisation, or how uncertainty propagates through the marine weather routing process. Of interest is how Polynesian seafaring technology could have contributed towards the length of 40 the long pause and how competing factors and sources of uncertainty could have influenced the result.
A review of Polynesian seafaring technology has allowed the performance of the earliest recorded voyaging canoe, the Tongiaki to be predicted. A novel methodology was developed to quantify the influence of weather, performance and 45 numerical uncertainty on the minimum time taken to complete a specific voyage. The ability to use Bayesian Belief Networks (BBNs) to model the reliability within the routing algorithm was shown to improve the chances of completing a voyage using an autonomous sailing craft, a modern naval architectural problem. By applying the novel methodology it was found that the Tongiaki was only able 50 to complete voyages between Samoa and Aituitaki, the voyage bridging West and East Polynesia, under El Niño conditions. The windward ability of a canoe was found to be more influential than speed increases from simulations generated by using a parametric voyaging canoe model. The trend in simulated Polynesian canoe performance mirrors that seen in the spatial development in Polynesian 55 seafaring technology.
Although sweet potato (Ipomoea batatas) is gaining importance in West Africa, it remains uncertain whether the research is adequately advanced to support the promotion of this crop in the region. Consequently, this systematic review of 125 articles provides a detailed overview of studies focused on sweet potatoes in West Africa. The paper explores various bibliometrics, the research geographic spread, and the topics discussed (e.g., food security and nutrition, climate resilience, livelihoods). The study indicates that sweet potato has the potential to address multiple issues in West Africa, including food and nutrition insecurity (especially micronutrient deficiencies, e.g., vitamin A) as well as poverty. However, it also reveals significant research gaps in terms of geographical and thematic areas. From a geographical perspective, research is primarily conducted in Nigeria and Ghana. From a thematic perspective, there are deficiencies in areas like economics and social sciences, applications in animal husbandry, marketing, use of leaves, irrigation methods, and impacts on climate resilience and livelihoods. There is a pressing need for collaborative research and knowledge exchange among nations to fully realize the potential of sweet potato and develop its value chains to contribute to sustainable socio-economic development across West Africa.
Ipomoea batatas (L.) Lam., the sweet potato, is one of the most important crops worldwide and a staple in many countries. It is cultivated in warm countries for its edible storage roots, and thousands of cultivars and landraces have been recorded worldwide. It is the best-known member of the genus Ipomoea L., the morning glories, a group of over 800 species present in all tropical and subtropical regions of the World (Muñoz-Rodríguez et al. 2019).
Here, we report on the results of microCT scanning and Accelerator Mass Spectrometry (AMS) radiocarbon dating of fragments of charred archaeological parenchyma collected from surface deposits at Nombe rockshelter in the highlands of Papua New Guinea. Five fragments are taxonomically identified as sweet potato (Ipomoea batatas). Two subsamples from the largest fragment yield a combined AMS date range of c. 300–148 calBP (with median probabilities of 187 and 195 calBP respectively). Although post‐dating European voyaging in the Indo‐Pacific, these findings contribute to the corpus of information regarding the antiquity of sweet potato on the island of New Guinea. Nous présentons ici les résultats d’imagerie par tomographie axiale (microCT) et de datations radiocarbone par spectrométrie de masse (AMS) réalisées sur des restes calcinés de parenchymes collectés en surface dans l’abri de Nombe, dans les hautes terres de Papouasie‐Nouvelle Guinée. Cinq fragments ont été identifiés taxonomiquement comme des restes de patate douce (Ipomoea batatas). Deux échantillons du plus gros fragment ont fourni une date AMS calibrée de 300‐148 cal BP (avec des probabilités respectives de 187 et 195 cal BP). Bien que ces découvertes soient postérieures aux voyages européens dans l’Indo‐Pacifique, elles contribuent néanmoins au corpus d’informations relatives à l’ancienneté de la patate douce dans la région de Nouvelle‐Guinée.
Te Parapara Garden is the only complete pre-European-style Māori horticultural garden in the world. Historically inspired and empirically researched, it lies within the Hamilton Gardens on a young river terrace immediately adjacent to the Waikato River in Hamilton (Kirikiriroa), Aotearoa New Zealand. In this article, Wiremu Puke (Ngāti Wairere, Ngāti Porou) – a tohunga whakairo (master carver, including using pre-steel tools) and a tohunga whakapapa (genealogical expert on his tribal affiliations) of Ngāti Wairere (the mana whenua, or first people of the traditional ancestral tribal lands of Kirikiriroa) – describes the design and development of Te Parapara Garden from its initial concept in 2003 and the construction of its many features, including the waharoa (gateway), pou (carved pillars), pātaka (storehouse), whatarangi (small storehouse), taeapa (fencing) and rua kūmara (underground storage pit), and the sourcing and use of kōkōwai (red ochre). The garden was completed in 2010. Its ongoing functioning, including the annual planting and harvesting of traditional pre-European kūmara (sweet potato) using modified, mounded soils (puke or ahu), is also covered. The unique Te Parapara Garden is of great cultural importance and a source of pride, knowledge and understanding for national and international visitors and empirical and academic researchers.
The history of sweet potato in the Pacific has long been an enigma. Archaeological, linguistic, and ethnobotanical data suggest that prehistoric human-mediated dispersal events contributed to the distribution in Oceania of this American domesticate. According to the "tripartite hypothesis," sweet potato was introduced into Oceania from South America in pre-Columbian times and was then later newly introduced, and diffused widely across the Pacific, by Europeans via two historically documented routes from Mexico and the Caribbean. Although sweet potato is the most convincing example of putative pre-Columbian connections between human occupants of Polynesia and South America, the search for genetic evidence of pre-Columbian dispersal of sweet potato into Oceania has been inconclusive. Our study attempts to fill this gap. Using complementary sets of markers (chloroplast and nuclear microsatellites) and both modern and herbarium samples, we test the tripartite hypothesis. Our results provide strong support for prehistoric transfer(s) of sweet potato from South America (Peru-Ecuador region) into Polynesia. Our results also document a temporal shift in the pattern of distribution of genetic variation in sweet potato in Oceania. Later reintroductions, accompanied by recombination between distinct sweet potato gene pools, have reshuffled the crop's initial genetic base, obscuring primary patterns of diffusion and, at the same time, giving rise to an impressive number of local variants. Moreover, our study shows that phenotypes, names, and neutral genes do not necessarily share completely parallel evolutionary histories. Multidisciplinary approaches, thus, appear necessary for accurate reconstruction of the intertwined histories of plants and humans.
In the Mount Hagen area of central New Guinea, warfare has been replaced since the arrival of the Europeans by a vigorous development of moka, a competitive ceremonial exchange of wealth objects. The exchanges of pigs, shells and other valuables are interpreted as acting as a bond between groups, and as a means whereby individuals, notably the big-men, can maximize their status. Professor Strathern analyses the ways in which competition between big-men actually takes place, and the effects of this competition on the overall political system.
Most of the world's poorest smallholders depend on tropical roots and tubers crops as their principal source of food and nutrition. These species produce large quantities of dietary energy and have stable yields under difficult environmental conditions. The most important crops are cassava, sweet potato, yam and the aroids, sharing important common traits such as bulkiness, post-harvest perishability and vegetative propagation. This book compiles the most up to date information on the origin, genetics, physiology, agronomy, pests and diseases and post harvest processing of these crops, while attempting to provide ideas for further research and development.
Apart from their local significance in terms of reconstructing the prehistory of the Cook Islands, the archaeological finds of sweet potato in central eastern Polynesia by around AD 1000 raise important issues as to cultural contact with South America. The recovery of Impomoea batatas tuber remains demonstrates the feasibility of identifying carbonised soft tissues of root or tuber crops from other Oceanic sites or indeed sites in other tropical regions of the world. -J.Sheail
A multidimensional conceptual framework is advanced that characterizes early agriculture as a subset of human-environment interactions. Three cross-articulating dimensions of human-environment interaction are considered that accommodate the varied expressions of early agriculture in different parts of the world: spatial scales, transformative mechanisms, and temporalities of associated phenomena. These ideas are applied and exemplified at two different scales of resolution—contextual and comparative—in terms of early agricultural development in the highlands of New Guinea and the dispersal of domesticates from New Guinea into Island Southeast Asia.
Our focus is the Papua New Guinea Highlands, which are continuous across Southern Highlands, Enga, Western Highlands, Simbu, and Eastern Highlands Provinces; but from time to time we look beyond the Indonesian border to Irian Jaya, where, separated from the above by lightly peopled mountain country, are the Baliem and Western Dani and, beyond them, the Kapauku of the Paniai lakes. In a sense, agriculture has been involved in most discussion of sociocultural development in this region. At European contact, everywhere within the last 60 years, the Indo-Pacific staples of lowland New Guinea, such as Colocasia taro and Dioscorea yam, were minor crops. Agriculture was dominated by the tropical American sweet potato (Ipomoea batatas), a food plant superior to taro and yam in its yield and maturation at altitude, and in its tolerance of poor and agriculturally depleted soils; but the sweet potato's appearance in the island is generally agreed to have been post-Magellanic. Watson argued for an Ipomoean Revolution, in which the sweet potato transformed a region where before there had been only low levels of agricultural activity and population. This is the issue that underlies our review of recent archaeological and ethnographic work on Highlands societies and their developmental contexts. -from Authors
With an eye to their own life goals, the native peoples of Pacific Islands unwittingly present to anthropologists a generous scientific gift: an extended series of experiments in cultural adaptation and evolutionary development. They have compressed their institutions within the confines of infertile coral atolls, expanded them on volcanic islands, created with the means history gave them cultures adapted to the deserts of Australia, the mountains and warm coasts of New Guinea, the rain forests of the Solomon Islands. From the Australian Aborigines, whose hunting and gathering existence duplicates in outline the cultural life of the later Paleolithic, to the great chiefdoms of Hawaii, where society approached the formative levels of the old Fertile Crescent civilizations, almost every general phase in the progress of primitive culture is exemplified.
We analysed a representative collection of New World sweet potato landraces (329 accessions from Mexico to Peru) with both chloroplast and nuclear microsatellite markers. Both kinds of markers supported the existence of two geographically restricted genepools, corresponding to accessions from the north-western part of South America and accessions from the Caribbean and Central America region. Our conservative cpSSRs markers revealed that the divergence between the two haplotype groups is associated with numerous mutation events concerning various markers, supporting the idea that this divergence may be ancient, predating domestication. For both kinds of markers, we found no significant difference in diversity between the two genepools and detected region-specific alleles in both groups. Previous studies have favoured the hypothesis of a single domestication of this crop. Our analysis suggests at least two independent domestications, in Central/Caribbean America and in the north-western part of South America. Sweet potato was then dispersed from these centres throughout tropical America. Comparison of nuclear and chloroplast data suggests that exchanges of clones and sexual reproduction were both important processes in landrace diversification in this clonally propagated crop. Our analysis provides useful tools for rationalizing the conservation and use of sweet potato germplasm collections.