Consilience of genetics and archaeobotany in the entangled history of rice

Abstract

Major leaps forward in understanding rice both in genetics and archaeology have taken place in the past decade or so-with the publication of full draft genomes for indica and japonica rice, on the one hand, and with the spread of systematic flotation and increased recovery of archaeological spikelet bases and other rice remains on early sites in China, India and Southeast Asia. This paper will sketch a framework that coherently integrates the evidence from these burgeoning fields. This framework implies a reticulate framework in the phylogeny of early cultivated rice, with multiple starts of cultivation (two is perhaps not enough) but with the key consolidations of adaptations that must have been spread through hybridisation and therefore long-distance cultural contacts.Archaeobotanical evidence allows us to document the gradual evolutionary process of domestication through rice spikelet bases and grain size change. Separate trends in grain size change can be identified in India and China. The earliest centre of rice domestication was in the Yangtze basin of China, but a largely separate trajectory into rice cultivation can be traced in the Ganges plains of India. Intriguingly, contact-induced hybridisation is indicated for the early development of indica in northern India, ca. 2000 BC. An updated synthesis of the interwoven patterns of the spread of various rice varieties throughout Asia and to Madagascar can be suggested in which rice reached most of its historical range of important cultivation by the Iron Age. The distribution of wild rice and genetic diversity in domesticated ricesRice is a highly diversified crop, being grown from the equator to over 40°N, from sea-level ca. 2,700 m in parts of the Himalayas and in a wide ecological range of cultivation systems. Although there is much less ecological variation found within its wild progenitor complex (Oryza rufipogon and Oryza nivara), these are nonetheless distributed over a wide geographical range and a spectrum of ecological niches from permanent to seasonal wetlands. As the origins of cultivation must have developed in places where hunter-gatherers were utilising wild populations, the distribution of the wild progenitor, in the past when cultivation began, is a key element in identifying the origins of rice. There are three lines of approach to inferring this without archaeological evidence, including (1) the Electronic supplementary material The online version of this article (

The Checkered Prehistory of Rice Movement Southwards as a Domesticated Cereal—from the Yangzi to the Equator

“…The archaeological chronology of development and outflow of Neolithic lifestyles in the eastern Asian region can be summarized as follows (Bellwood 2005: chapters 6, 7, and 10;Hung 2008, 2010;Fuller et al 2010;Bellwood et al 2011b):…”

An Son Ceramics in the Neolithic Landscape of Mainland Southeast Asia

“…Rivers and their tributaries were likely to have been of great importance to the movement of people and ideas in the past. The Neolithic occupation of Vietnam exhibits evidence of contact with China and other regions of MSEA, leading to suggestions that agricultural practices travelled from the north via rivers and/or along the coast (Fuller et al 2010;. The Neolithic sites exhibit the oldest evidence of cultivation in MSEA, including rice and other crops, supplemented by a hunter-gatherer-fisher economy.…”

“…Whilst there is general acceptance for a Neolithic transference from southern China to MSEA, with a potentially ultimate origin in the Yangtze River, its timing, events and routes via river courses or coastal lowlands continue to be discussed (Higham 2002;Rispoli 2007;Fuller et al 2010;Nakamura 2010;Zhang and Hung 2010;Zhao 2010;Bellwood 2011;Castillo 2011;Higham et al 2011;Lu 2011). Increasingly, more interpretations posit multiple movements over a period of time and the adoption of selected traits in the transition to agriculture (Zhang and Hung 2010).…”

Twenty-first century approaches to ancient problems: Climate and society

“…Correlations between changes in climate and shifts in agricultural regimes/potential productivity have been noted in many areas of the world, including the British Isles (29) and the Middle East (60). For example, rice was first cultivated in one or two centers in the Yangzi river valley that provided a great deal of summer warmth and ample water resources (61). How were farmers able to adapt this water-and heat-loving plant to higher altitudes and latitudes?…”