Papers by Cristina Castillo
PNAS, 2022
Asian rice (Oryza sativa L.) is consumed by more than half of the world's population. Despite its... more Asian rice (Oryza sativa L.) is consumed by more than half of the world's population. Despite its global importance, the process of early rice domestication remains unclear. During domestication, wild rice (Oryza rufipogon Griff.) acquired non-seed-shattering behavior, allowing humans to increase grain yield. Previous studies argued that a reduction in seed shattering triggered by the sh4 mutation led to increased yield during rice
domestication, but our experiments using wild introgression lines show that the domesticated sh4 allele alone is insufficient for shattering loss in O. rufipogon. The interruption of abscission layer formation requires both sh4 and qSH3 mutations, demonstrating that the selection of shattering loss in wild rice was not as simple as previously suggested. Here we identified a causal single-nucleotide polymorphism at qSH3 within the seed-shattering gene OsSh1, which is conserved in indica and japonica subspecies but absent in the circum-aus group of rice. Through harvest experiments, we further demonstrated that seed shattering alone did not significantly impact yield; rather, yield increases were observed with closed panicle formation controlled by SPR3 and further augmented by nonshattering, conferred by integration of sh4 and qSH3 alleles. Complementary manipulation of panicle shape and seed shattering results in a mechanically stable panicle structure. We propose a stepwise route for the earliest phase of rice domestication, wherein selection of visible SPR3-controlled closed panicle morphology
was instrumental in the sequential recruitment of sh4 and qSH3, which together led to the loss of shattering.
Antiquity, 2021
Established chronologies indicate a long-term ‘Hoabinhian’ hunter-gatherer occupation of Mainland... more Established chronologies indicate a long-term ‘Hoabinhian’ hunter-gatherer occupation of Mainland Southeast Asia during the Terminal Pleistocene to Mid-Holocene (45 000–3000 years ago). Here, the authors re-examine the ‘Hoabinhian’ sequence from north-west Thailand using new radiocarbon and luminescence data from Spirit Cave, Steep Cliff Cave and Banyan Valley Cave. The results indicate that hunter-gatherers exploited this ecologically diverse region throughout the Terminal Pleistocene and the Pleistocene–Holocene transition, and into the period during which agricultural lifeways emerged in the Holocene. Hunter-gatherers did not abandon this highland region of Thailand during periods of environmental and socioeconomic change.
Archaeological and Anthropological Sciences, 2020
The present paper reports the first systematic archaeobotanical evidence from Bangladesh together... more The present paper reports the first systematic archaeobotanical evidence from Bangladesh together with direct AMS radiocarbon dates on crop remains. Macro-botanical remains were collected by flotation from two sites, Wari-Bateshwar (WB), an Early Historic archaeological site, dating mainly between 400 and 100 BC, with a later seventh century AD temple complex, and Raghurampura Vikrampura (RV), a Buddhist Monastery (vihara) located within the Vikrampura city site complex and dating to the eleventh and sixteenth centuries AD. Despite being a tropical country, with high rainfall and intensive soil processes, our work demonstrates that conventional archaeobotany, the collection of macro-remains through flotation, has much potential towards putting together a history of crops and agricultural systems in Bangladesh. The archaeobotanical assemblage collected from both sites indicates the predominance of rice agriculture, which would have been practiced in summer. Spikelet bases are of dome...
Annals of Botany, 2020
Background Vegetatively propagated crops are globally significant in terms of current agricultura... more Background Vegetatively propagated crops are globally significant in terms of current agricultural production, as well as for understanding the long-term history of early agriculture and plant domestication. Today, significant field crops include sugarcane (Saccharum officinarum), potato (Solanum tuberosum), manioc (Manihot esculenta), bananas and plantains (Musa cvs.), sweet potato (Ipomoea batatas), yams (Dioscorea spp.) and taro (Colocasia esculenta). In comparison to sexually-reproduced crops, especially cereals and legumes, the domestication syndrome in vegetatively-propagated field crops is poorly defined. Aims and scope Here, a range of phenotypic traits potentially comprising a syndrome associated with early domestication of vegetatively-propagated field crops is proposed, including: mode of reproduction, yield of edible portion, ease of harvesting, defensive adaptations, timing of production and plant architecture. The archaeobotanical visibility of these syndrome traits is...
Genetic Resources and Crop Evolution, 2019
Cajanus cajan (L.) Millsp. commonly known as pigeonpea, red gram or gungo pea is an important gra... more Cajanus cajan (L.) Millsp. commonly known as pigeonpea, red gram or gungo pea is an important grain legume crop, particularly in rain-fed agricultural regions in the semi-arid tropics, including Asia, Africa and the Caribbean. This paper provides a baseline for the study of the domestication and early history of C. cajan, through reviewing its modern wild distribution, seed morphometrics of wild and domesticated populations, historical linguistics and the archaeological record. The distribution of wild populations, including published records and additional herbarium collections, suggest that the wild habitats of pigeonpea were at the interface of the forest-edge areas and more open savanna plains in eastern Peninsular India (e.g. Telangana, Chattisgarh, Odisha). Early archaeological finds presented here have been recovered from both the Southern peninsula and Odisha. Historical linguistic data suggests early differentiation into longer and shorter growing season varieties, namely arhar and tuar types, in prehistory. Pigeonpea had spread to Thailand more than 2000 years ago. Measurements of seeds from modern populations provide a baseline for studying domestication from archaeological seeds. Available measurements taken on archaeological Cajanus spp. suggest that all archaeological collections thus far fall into a domesticated Length:Width ratio, while they may also pick up the very end of the trend towards evolution of larger size (the end of the domestication episode) between 3700 and 3200 years BP. This suggests a trend over time indicating selection under domestication had begun before 3700 years ago and can be inferred to have started 5000-4500 years ago.
The Holocene, 2018
We model the prehistoric dispersals of two rice varieties, japonica and proto- indica, across Asi... more We model the prehistoric dispersals of two rice varieties, japonica and proto- indica, across Asia using empirical evidence drawn from an archaeobotanical dataset of 400 sites from mainland East, Southeast and South Asia. The approach is based on regression modelling wherein goodness of fit is obtained from log–log quantile regressions of the archaeologically inferred age versus a least-cost distance from the origin(s) of dispersal. The Fast Marching method is used to estimate the least-cost distances based on simple geographical features. We explicitly test three hypotheses for the arrival of japonica rice to India where, it has been proposed, it hybridized with the indigenous proto- indica, subsequently spreading again throughout India. Model selection, based on information criteria, highlights the role of the Inner Asia Mountain Corridor in introducing japonica rice into northeast India, followed closely by a ‘mixed-route’ model, where japonica was also almost simultaneously intr...
Antiquity, 2018
Large, 'complex' pre-Neolithic hunter-gather communities thrived in southern China and northern V... more Large, 'complex' pre-Neolithic hunter-gather communities thrived in southern China and northern Vietnam, contemporaneous with the expansion of farming within the region. Our research at the Con Co Ngua site in northern Vietnam suggests that such hunter-gatherer populations shared similar characteristics with early farming communities: high disease loads, pottery, complexity in mortuary practice and access to stable sources of carbohydrates and protein. The only substantive difference was in the use of domesticated plants and 2 animals-a difference effectively viewed as representing alternative responses to optimal climatic conditions. Our work suggests that the supposed correlation between farming and a decline in health may, in some instances, need to be reassessed.
Antiquity, 2018
New evidence from archaeological investigations in northeast Thailand shows a transition in rice ... more New evidence from archaeological investigations in northeast Thailand shows a transition in rice farming towards wetland cultivation that would have facilitated greater yields and surpluses. This evidence, combined with new dates and palaeoclimatic data, suggests that this transition took place in the Iron Age, at a time of increasingly arid climate, and when a number of broader societal changes become apparent in the archaeological record. For the first time, it is possible to relate changes in subsistence economy to shifts in regional climate and water-management strategies, and to the emergence of state societies in Southeast Asia.
Quaternary International, 2017
Rach Nui is a late Neolithic settlement of hunter-gatherers in southern Vietnam. However, the sit... more Rach Nui is a late Neolithic settlement of hunter-gatherers in southern Vietnam. However, the site also has a series of mortared floors corresponding to a sedentary lifestyle, where the inhabitants continued to live in the same area and repaired or replaced their floors over a period of 150 years. The inhabitants relied on a mixed economy that included domesticated and gathered plants, as well as hunted and managed animals. Although, there is evidence for the consumption of domesticated rice and foxtail millet, the inhabitants were mainly huntergatherers who relied on their surrounding mangrove and swamp forest habitats for most of their food requirements. From the archaeobotanical work done, it appears that the domesticated cereals, rice and foxtail millet, found at the site were imported. On the other hand, sedge nutlets and parenchyma were identified in high frequencies and were probably locally sourced, suggesting that foraging and/or vegeculture played a major role in the economy of Rach Nui.
Archaeology International, 2016
The archaeology of rice has made important methodological advances over the past decade that have... more The archaeology of rice has made important methodological advances over the past decade that have contributed new data on the domestication process, spread and ecology of cultivation. Growing evidence from spikelet bases indicates that non-shattering, domesticated forms evolved gradually in the Yangtze basin and that there were at least two distinct processes around the Middle Yangtze region pre-dating 6000 BC, and the in the Lower Yangtze region between 6000 and 4000 BC. Early rice cultivation in these areas was based on wet field ecologies, in contrast to rainfed rice that is indicated among the earliest systems in India. When rice first spread north it was not entirely suited to shorter temperate summer growth seasons, and we are able to infer from high levels of apparently green-harvested spikelets that genetic adaptations to temperate conditions evolved after 2000 BC. When rice first spread south, to mainland Southeast Asia, after 2500 BC, it was grown in rainfed, dry ecologies...
Antiquity, 2016
Thong on the Thai-Malay Peninsula show evidence of crosscultural interactions, particularly betwe... more Thong on the Thai-Malay Peninsula show evidence of crosscultural interactions, particularly between India to the west and Southeast Asia to the east. Archaeobotanical analysis of various cereals, beans and other crops from these assemblages sheds light on the spread and adoption of these species for local agriculture. There is also early evidence for the trade of key commodities such as cotton. The plant remains illustrate a variety of influences and networks of contact across South and Southeast Asia during the late first millennium BC.
Oxford Handbooks Online, 2016
Rice (Oryza) is one of the world’s most important and productive staple foods, with highly divers... more Rice (Oryza) is one of the world’s most important and productive staple foods, with highly diverse uses and varieties. We use archaeobotany, culture, history, and ethnobotany to trace the history of the development of sticky (or glutinous) forms. True sticky rice is the result of a genetic mutation that causes a loss of amylose starch but higher amylopectin content. These mutations are unknown in wild populations but have become important amongst cultivars in East and Southeast Asia (unlike other regions). In the same region, other cereals have also evolved parallel mutations that confer stickiness when cooked. This points to a strong role for cultural history and food preparation traditions in the genetic selection and breeding of Asian cereal varieties. The importance of sticky rice in ritual foods and alcoholic beverages in East and Southeast Asia also suggests the entanglement of crop varieties and culturally inherited food traditions and ritual symbolism.
PLOS ONE, 2015
We have compiled an extensive database of archaeological evidence for rice across Asia, including... more We have compiled an extensive database of archaeological evidence for rice across Asia, including 400 sites from mainland East Asia, Southeast Asia and South Asia. This dataset is used to compare several models for the geographical origins of rice cultivation and infer the most likely region(s) for its origins and subsequent outward diffusion. The approach is based on regression modelling wherein goodness of fit is obtained from power law quantile regressions of the archaeologically inferred age versus a least-cost distance from the putative origin(s). The Fast Marching method is used to estimate the least-cost distances based on simple geographical features. The origin region that best fits the archaeobotanical data is also compared to other hypothetical geographical origins derived from the literature, including from genetics, archaeology and historical linguistics. The model that best fits all available archaeological evidence is a dual origin model with two centres for the cultivation and dispersal of rice focused on the Middle Yangtze and the Lower Yangtze valleys.
Journal of Indo-Pacific Archaeology, 2014
Non Ban Jak is a large, moated site located in the upper Mun Valley, Northeast Thailand. Excavati... more Non Ban Jak is a large, moated site located in the upper Mun Valley, Northeast Thailand. Excavations over three seasons in 2011-4 have revealed a sequence of occupation that covers the final stage of the local Iron Age. The site is enclosed by two broad moats and banks, and comprises an eastern and a western mound separated by a lower intervening area. The first season opened an 8 by 8 m square on the eastern mound, while the second and third seasons uncovered part of the low terrain rising into the western mound, encompassing an area of 25 by 10 m. The former revealed a sequence of industrial, residential and mortuary activity that involved the construction of houses, kiln firing of ceramic vessels and the interment of the dead within residences. The latter involved four phases of a late Iron Age cemetery, which again incorporated house floors and wall foundations, as well as further evidence for ceramic manufacture. The excavation sheds light on a late Iron Age town occupied at the threshold of state formation.
The Journal of Island and Coastal Archaeology, 2015
ABSTRACT We examine the southern Vietnamese site of Rach Nui, dated to between 3390 and 3850 cal ... more ABSTRACT We examine the southern Vietnamese site of Rach Nui, dated to between 3390 and 3850 cal BP, in the context of threemajor aspects of the Neolithic in Mainland Southeast Asia: mound formation and chronology, construction techniques, and subsistence economy. Results indicate that this ca. 75 m in diameter, 5 m high mound, comprising over a dozen phases of earthen platforms, upon which were raised sophisticated wooden structures, was built in <200 years. While consuming domesticatedmillet, rice, and occasionally dogs and pigs, the main subsistence orientation includedmanaged tubers and fruits and a range of mangrove ecosystem taxa: catfishes, turtles, crocodiles, monitor lizards, macaques and langurs, to name a few. This combined vegeculture foraging lifeway in a mangrove forested environment, likely in the context of a tradable goods extractive industry, adds to a growing picture of significant diversity, and sophisticated construction skills in the Southeast Asian Neolithic. link to pdf: http://www.tandfonline.com/eprint/hG72TYSNckFWAE8pwa28/full
Encyclopedia of Global Archaeology, 2014
The Holocene, 2011
We review the origins and dispersal of rice in Asia based on a data base of 443 archaeobotanical ... more We review the origins and dispersal of rice in Asia based on a data base of 443 archaeobotanical reports. Evidence is considered in terms of quality, and especially whether there are data indicating the mode of cultivation, in flooded (‘paddy’ or ‘wet’) or non-flooded (‘dry’) fields. At present it appears that early rice cultivation in the Yangtze region and southern China was based on wet, paddy-field systems from early on, before 4000 bc, whereas early rice in northern India and Thailand was predominantly dry rice at 2000 bc, with a transition to flooded rice documented for India at c. 1000 bc. On the basis of these data we have developed a GIS spatial model of the spread of rice and the growth of land area under paddy rice. This is then compared with a review of the spread of ungulate livestock (cattle, water buffalo, sheep, goat) throughout the Old World. After the initial dispersal through Europe and around the Mediterranean (7000–4000 bc), the major period of livestock expansi...
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Papers by Cristina Castillo
domestication, but our experiments using wild introgression lines show that the domesticated sh4 allele alone is insufficient for shattering loss in O. rufipogon. The interruption of abscission layer formation requires both sh4 and qSH3 mutations, demonstrating that the selection of shattering loss in wild rice was not as simple as previously suggested. Here we identified a causal single-nucleotide polymorphism at qSH3 within the seed-shattering gene OsSh1, which is conserved in indica and japonica subspecies but absent in the circum-aus group of rice. Through harvest experiments, we further demonstrated that seed shattering alone did not significantly impact yield; rather, yield increases were observed with closed panicle formation controlled by SPR3 and further augmented by nonshattering, conferred by integration of sh4 and qSH3 alleles. Complementary manipulation of panicle shape and seed shattering results in a mechanically stable panicle structure. We propose a stepwise route for the earliest phase of rice domestication, wherein selection of visible SPR3-controlled closed panicle morphology
was instrumental in the sequential recruitment of sh4 and qSH3, which together led to the loss of shattering.
domestication, but our experiments using wild introgression lines show that the domesticated sh4 allele alone is insufficient for shattering loss in O. rufipogon. The interruption of abscission layer formation requires both sh4 and qSH3 mutations, demonstrating that the selection of shattering loss in wild rice was not as simple as previously suggested. Here we identified a causal single-nucleotide polymorphism at qSH3 within the seed-shattering gene OsSh1, which is conserved in indica and japonica subspecies but absent in the circum-aus group of rice. Through harvest experiments, we further demonstrated that seed shattering alone did not significantly impact yield; rather, yield increases were observed with closed panicle formation controlled by SPR3 and further augmented by nonshattering, conferred by integration of sh4 and qSH3 alleles. Complementary manipulation of panicle shape and seed shattering results in a mechanically stable panicle structure. We propose a stepwise route for the earliest phase of rice domestication, wherein selection of visible SPR3-controlled closed panicle morphology
was instrumental in the sequential recruitment of sh4 and qSH3, which together led to the loss of shattering.
emergence of state societies in Southeast Asia.
From UCL’s IoA Early Rice Project. Version 1.1 1 March 2019
By Prof Dorian Q Fuller, Professor of Archaeobotany, University College London (UCL), Dr Cristina Castillo, Post-doctoral archaeobotanist, UCL and
Dr Eleanor Kingwell-Banham, Post-doctoral archaeobotanist, UCL
This handbook is designed to provide brief practical advise to archaeologists who want to study rice. It includes information on the types of rice, how to identify domesticated rice, ways to use rice grains/seeds and rice phytoliths, and information on how to sample for macrobotanical remains and phytoliths.
Further details can be found at www.ucl.ac.uk/rice in due course.