Tuesday 22 December 2009

the trouble with two-row barley

I still seem to be playing blog catch-up, but I had to record something from a few months ago, which should be forcing us to think about the prehistory of barley in a whole new way. .. Palmer et al. of the Warwick molecular archaeobotany lab group of Robin Allaby published a major paper on plant ancient DNA in PLoSone this summer, "Archaeogenetic Evidence of Ancient Nubian Barley Evolution from Six to Two-Row Indicates Local Adaptation." On the one hand it has some nice clear ancient DNA results from the Nubian site of Qasr Ibrim, which allows these samples to be placed phylogenetically in relation to the gene the control whether barley is two-row or six-row. They have found what at first seems counter intuitive-- that all the barley samples have the six-row mutation, despite the fact that Nubian barley is usually regarded archaeologically as two-row, based on its symmetrical grains.

Friday 18 December 2009

Cereal in Libya earlier than Egypt? New data from Huah Fteah

The spread of agriculture to Egypt presents a number of contrasts from that in Europe of east of the Fertile Crescent. For one thing it seems to be long delayed, with our conventional dates for the earliest cereal agriculture in Egypt, such as in the Fayum at 5000-4500 BC-- by contrast cereal agriculture is established in Greece and Pakistan by 7000 BC. What is more Near Eastern animal domesticates (sheep and goat) had reached Egypt at least 1000-1500 years earlier and spread rapidly through the Sahara. New data from Libya, rather than the Nile, suggests a new wrinkle in this story: cereal agriculture did spread earlier (by 6000 BC?), and probably was established in part of the Nile Delta, but made little headway up the Nile. How have I come to this conclusion?  [ed. June 2010: but see my own comment on the radiocarbon dates that have now overturned this]

In the latest issue of the journal Libyan Studies (vol. 40, 2009), there is a long preliminary report on the new Society for Libyan Studies/ Cambridge project at the famous Haua Fteah rock shelter, and thereabouts, the "The Cyrenaican Prehistory Projecy 2009" As part of this renewed work systematic archaeobotany is being carried out both at Haua and at nearby Hagfet al-Gama. Results from the macro-botanical work by Jacob Morales (normally based on the island of Gran Canaria) are presented over a few pages in Libyan Studies (pp. 83-88), and seem to be highly significant, if understated. Seeds are generally few and not surprisingly most are wild species. But of note is the the occurrence of barley grains and free-threshing tetraploid wheat (T. durum) rachis from the 2008 samples of Hagfet al-Gama. These are yet to be directly dated, but the cultural association is with the socalled Lybico-Capsian period, characterized by being non-ceramic and conventionally termed "Mesolithic". The Neolithic, in which older work identified domesticated sheep and goats along with ceramics, dates from ca. 5500 cal.BC-- based on the the latest radiocarbon dates. These finds from the Lybico-Capsian then suggest that domesticated cereals, deriving from the Near East, were already present somewhat earlier. Of course we must await more data, and direct dates; as well as results from new faunal analyses to see if any domestic fauna occurred alongside this pre-ceramic Libyan cereals... at present, however, we have tantalizing prospect of an earlier, hitherto undetected diffusion of cereals to northern (Mediterranean) Libyan, presumably over land via the Nile Delta-- where equivalent evidence is likely buried under meters of alluvium. Such a scenario makes the delayed diffusion of cereals into Middle or Upper Egypt and the Nile Valley all the more striking. In this region the 'Primary Pastoral Community' (sensu Wengrow) seems indeed to have been rather averse to cereal farming.

Wednesday 4 November 2009

rice genetics watch: structure in Chinese rices but not domestication genes?

  • In the Oct. 2009 issue of Theoretical and Applied Genetics, a large Chinese research group (Zhang et al.) looked Genetics structure among Chinese rice landraces, with over 3000 Chinese rice populations. They find clear population structure, not just between indica and japonica as expected, but also within each of these. Interesting they report that the structure in indica seems to relate to flowering time (early, middle or late flowering varieties), which suggests that early differentiation after indica originated may be focused on seasonality (and constraints of seasonal land and water availability). In the case of japonica (primarily temperate japonica one presumes), seasonality is pretty much always restricted to the warm wet summer, as China has dry, cool winters that are not conducive to rice. Instead structure seems to divide Chinese japonica landraces on the ground of soil and water adaptations, and whether they are best grown ion paddies or on upland rainfall. Indeed, as predicted from the archaeology the earliest ecological efforts in rice domestication in China are likely to have focused on water manipulation (see Fuller & Qin in World Archaeology), while early dispersal must have also seen diversification in rainfed and less labour intensive systems of cultivation. On the whole an interesting approach that one would like see extended beyond China.

  • Another paper also with Zhang et al. authorship (but a different Zhang), that came out at the end of the summer in New Phytologist looked in more detail at the phylogeny of sh4 and qsh1 non-shattering (domestication) genes, and provides a coallescent model of their origin in terms of fixation time. Their estimate this trait should have been fixed in ~100 years seems a throwback to the kind results that models produced a decade ago, now at odds with the archaeobotanical evidence on domestication rates. The authors are at odds to explain this by positing thhat the now universal(?) sh4 domestication gene evolved after initial domestication and then diffused throughout rice (and replaced some earlier domestication genes). Not a particular elegant, nor historically/archaeologically compelling model. I am forced to assume that something is amiss in the math or the assumptions of the model. Can an apparent rapid bottleneck be artefact of another process in the way the apparent monophyly can (as per Allaby et al 2008). I also note that the phylogeny that relate domesticated sh4 to wild populations the same or a close gene, on the surface suggests an origin of sh4 from a Lao rufipogon or an Indian nivara-- but surely these wild taxa, and the indica and japonica types deriving from them should not group together in a population phylogeny when they have different chloroplast genomes (with a common ancestor in excess of 70,000 years ago!). Of course a Neighbourjoining tree, however much bolster by bootstraps and Montecarlo methods is still just a cluster analysis that is not a particularly logical or robust way to look for phylogenetic relationships within a species that hybridizes. Thus the method employed here denies the reticulate evolution which is so clearly a part of evolutionary story of rice, as so elegantly argued in earlier papers by Sang & Ge or more robustly in the recent papers of Kovach et al or McNally et al. I am therefore provisionally not at all sure what this sh4 data is actually telling us.

Rice genetics watch: many sweet-smelling genes

Although it is now a couple of months old, the paper by Kovach et al. (2009) in PNAS in August on the "Origin and Evolution of Fragrance in Rice" is an important contribution on the cultural history of rice. It is a clear example of selection by cultural preferences for rice that cooks a certain way, in this case with sweet or 'jasmine' aroma. Clearly many people from many cultural traditions have preferred their aromatic rices, whether Indian Basmati or Thai Jasmine rice, and this trait has been selected just as surely as ecological or domestication traits . But equally some people prefer otherwise, for their rice to smell of rice, which is true through Central China and much of east Asia.

While the responsible gene, BADH2, has been known for a while what is of interest here is that mutations in the sequence that produce fragrant rice have been distinguished and these have been tested over a very large diverse geographical sample. A single mutation is most widespread throughout regions with fragrant rice. It is clear that this originally from an early japonica lineage, presumably East Asian. And my inclination would be to see this evolving en route as Neolithic rice dispersed from S. China to SE Asia, (although it could be a later wave). But there are 9 additional more minor alternative mutations to the same gene to the same effect. They show clear geographical patterning, and the implication of that is this geographically separate groups have recurrently developed a preference for and selected for aromatic rices. It remains to be determined. Whether some of these were developed truly independently, with local fragrant mutations being kept or pushed to low frequency as the dominant BADH2 came in, or else these local aromatic variants were selected to mimick a preference developed after fragrant rice arrives. Of course the story may be different in different cases...

Tuesday 3 November 2009

Au Revoir Levi-Strauss

This blog returns, with a start, at the news that Claude Levi-Strauss died today. Startling because I hadn't even realized he was still alive! Although he probably hasn't influenced too many archaeobotanists, he certainly changed the way we think anthropologically about food, what is classed as edible, defined as cooked or rotten and how we refract much of what we mean to be cultural through a lens of cooking. In a general way, his brand linking cooking traditions to cultural cosmologies does run through the recently published (preliminary) study I wrote with Mike Rowlands on a "Macrogeography of Substances: Food & Sacrifice Traditions in East, West and South Asia" [pdf]. Levi-Strauss also plays the role of one of the characters (alongside the late Mary Douglas who lived and wrote to the ripe age of 86, less than Levi-Strauss' 100) interpreting archaeological feasts and human food sociality in Martin Jones' book Feast. As my tribute to Levi-Strauss I can think only to quote from one the myths he recounts on the origins of agriculture according to the Brazilian Munduruku:

In former times, game and cultivated plants were unknown to the Mundurucu.
They fed on wild tubers and tree fungi.
It was then that Karuebak, the mother of manoic, arrived and taught men the art of preparing it.
One day, she ordered her nephew to clear an area of forest, and she announced that soon bananas,
cotton, caras (Dioscorea), maize, the three varieties of manioc, watermelons, tobacco and cane
sugar would grow there. She ordered a ditch to be dug in the newly cleared area,
and asked to be buried in it. Care should be taken not to walk over her.
A few days later, Karuebak's nephew found that the plants listed by his aunt were growing on
the place where she lay; however, he inadvertantly walked on the hallowed ground, and
the plants at once stopped growing. This determined the size to which they have grown ever since.
A sorcerer, displeased at not having been informed of the miracle, caused the old woman to perish
in the hole where she lay. Since she was no longer there to advise them, the Indians
ate manikuera [manoic] raw, not knowing that this particular variety of manioc is poisonous
and emetic in that form. They all died, and next morning went up into the sky where they
became stars. Other Indians, who had eaten manikuera first raw and then cooked,
were transformed to honey flies. And those who licked the remains of the cooked manikuera
became the kind of bees which produce bitter, emetic honey..."

-- From Honey to Ashes, p. 56 (Levi-Strauss 1966)

Tuesday 25 August 2009

Millets and Mistakes

In Last week's Science the journalist Andrew Lawler, published an extended series of News Focus articles on Chinese civilization. The central piece focuses on the origins of civilization, highlighting for example the impressive urban settlement of Liangzhu (a kind of walled Neolithic Venice, many centuries before the Shang Dynasty) which ought to be better known to world archaeology than it is. (I had my own tour of some of the mutliple sites that compose it, and its multimedia museum, with site director Liu Bin in July). Also of note is his one page sidebar entitled "Go East, Young Archaeologist" on the specialists trained outside China, which features Jimmy Zhao, who has been instrumental in getting serious archaeobotany established in the minds and manners of Chinese archaeologists, and has been promoting flotation in China for the past decade.

What I would like to pursue here, however, are some observations on archaeobotany, and pick out some mistakes or misleading statements, with reference to the origins of millet agriculture which features in another sidebar, "Millets on the Move." Lawler begins which a point that seems to look increasingly true, that millet(s) were cultivated and presumably domesticated before rice, and were the staple foods of the northern China region where the classic Chinese civilization later emerged (focused on Erlitou rather than Liangzhu). He makes reference to the recent early dates (ca. 8000 BC) associated with Panicum miliaceum husk (lemma/palea) phytoliths reported from storage pits at Cishan (blogged previously). However, I must disagree the there is any hard evidence that the Panicum miliaceum at Cishan was morpholoigcally domesticated (i.e. non-shattering, with marked increased grain size, etc.), nor is there even clear evidence for cultivation, unless one assumes that large stores could only be ontained from cultivation, which in turn implies that we know the Early Holocene wild ecology of this species (which we don't) and that it did not form extensive collectible stands, as wild wheat, barley or rice or teosinte do (see discussion on my earlier Dadiwan blog and comment from L. Barton). I also must reiterate that there is much about the archaeology of the Cishan find (stratigraphiy, cultural context, and dating that require further work.

A lack of scientific clarity in Lawler's piece, however, is indicated in that millet is always used in the singular and the species (there are two major domesticates in ancient China) is never specified. And things get worse... as Lawler explored the hypothesis (favoured by Martin Jones and Cambridge millet group) that Panicum miliaceum (but NOT Setaria italica) spread before 5000 BC acroos temperate Eurasia from China to India. This hypothesis is plausible, but there is not yet any good clear data for this, only hints that it might yet emerge from ongoing and unpublished genetic work. Lawler acknowledges an alternative, which I would favour, that Panicum may have had a seperate domestication in the west somewhere near the Caspian and Black Seas. Well-dated, clearly-identified and numerically large assemblages of Panicum miliaceum outside China are mostly millenia later. To illustrate his case, Lawler produces a map which shows a major lapse in scientific clarity:

This map, although redrawn from that in Hunt et al (2008), is extremely mis-leading, especially when coupled with the text that hook-line-and-sinker swallows the notion that "millet" spread in the early Neolithic to Europe, without apparently realzing what "millet" is (or millets are). Millet is more than one species anyways despite the English misnomer-- in modern India one can find 12 domesticated species of "millet" in cultivation, with several more restrcted to Africa). The early dispersal of "millet" that Martin Jones favours, applies to broomcorn millet (Panicum miliaceum), as does the recent early find at Cishan, although Neolithic North China also boasts foxtail millet (Setaria italica), by about 6000 BC or so. For the map of Lawler, however, the "millet" in the caption actually means the genus Panicum or the genus Setaria, and does not require that these be cultivated or domesticated finds. What is most grevious in this map are the dots in Western Asia and Egypt. This map in its original, illustrated all reports identified to genus level of Setaria or Panicum-- both of which are major genera of grasses with multiple wild species-- in which the error margins of calibrated radiocarbon dates may place them as early as 5000 cal.BC (although often the dates are likely to be later). The dots in Western Asia, include sites such as Abu Hureyra in Syria, which is a well-known site to students of early wheat and barley agriculture. At this site it is argued (by Hillman et al. 2001) that wild rye and perhaps two-grained einkorn were brought into cultivation in the Late Pleistocene during the Younger Dryas, while later PPNB levels have evidence for domesticated wheats, barley and other Near Eastern crops. "Millet" is represented at this site by small number of wild Setaria, of either S. pumila or S. verticillata, and certainly not Setaria italica nor Panicum miliaceum. Other dots in Syria and Cyprus include Tell Mureybit, El Kowm, Bouqras, and Khirokhitia, which Lawler has now awarded domesticated Chinese millet in the Pre-Pottery Neolithic. Meanwhile, three dots occur in Egypt, representing Early Holocene "Neolithic" sites like Nabta Playa. These sites are Neolithic in the sense of having pottery but not in having agriculture. Archaeobotanical evidence from these sites shows wild savannah grass gathering, including wild sorghum and a range of other species, including wild Panicum sp. and wild Setaria sp., but there is certainly no suggestion that these were cultivars or related to S. italica or P. miliaceum. While Hunt et al (2008: S6) were explicit in trying avoid the pitfall of "over representing.... securely identified domesticated finds", Lawler appears to have jumped headfirst into this pit!

The dot in Iran (representing Daulatabad R37) is also problematic as early millet finds there are more likely local wild species, while evidence for domesticated Panicum miliaceum is probably later form the latter Third Millennium BC at Tepe Yahya (a time period which fits with the reports of broomcorn millet appearing in Yemen before 2000 BC-- see the recent Boivin/Fuller review dealing with the prehistory of Arabia). A more detailed and critical look at the sites in Europe would show that these also include numerous Setaria sp. and some Panicum sp. reports that are of local wild species. In addition, quantities of reported Panicum miliaceum are extremely low and it remains entirely plausible that these represent wild, weedy Panicum miliaceum subsp. ruderale as a weed rather than domesticated broomcorn as a crop-- a point admitted in the Hunt, Jones, et al. paper from which the map derives (see page S14). Of course there is a bias towards focuing of wheats and barley in European archaeobotany, and careful documentation of the early Panicum has been less thorough. More archaeobotanical efforts are needed in this direction, like that being pursued by the Cambridge millet group, but dumbing-down for, and misleading, the educated readers of Science is not.

Rice genetics watch: another grain size and yield gene

Shan et al. (2009) in Theoretical & Applied genetics report mapping of the gene spd6 which in wild O. rufipogon appeasr to reduced panicle size, grain number and grain size. This is likely to be yet another important gene that selection of early farming acted upon to increase yields (and grain sizes), along side genes such as qsw5, sw5, and gs3 that have been reported in recent years to affect grain size, and ghd7 and gn1a which affect p0anicle size and grain number. The new spd6 has been identified by a cross of a Hainan wild rice and the Chinese indica type, Teqing; it is not yet possible to draw any conclusions about the phylogenetic or geographical distributions of variants at this locus.

Friday 21 August 2009

Tuareg Trade & Archaeobotany

A new article in the latest Azania (in its new format), reports on the excavations at Tadmakka, in northeast Mali, carried out by Sam Nixon in recent years. These excavations of about 5 meters of stratigraphy produced a wide range of evidence for trans-Saharan trade between ca. 750 and 1400 AD, with a very significant cultural change, interpreted as 'Tuaregization' (a more Nomadic turn) from about 1300 AD. This article focuses on the material culture, the sequence, but includes summary comments on the animals and plant remains. Full details of the archaeobotany (carried out at UCL) are forthcoming.

This site provides the earliest significant evidence of trans-Saharan trade, including specifically gold trade and local gold coin production. Plant evidence also suggests a mixture of local crop-procduction, wild plant gathering and possible trade in grains; of particular interest is the evidence for free-threshing wheats-- but more on that when the archaeobotany is published. Some more information on the project is already available on-line here.

Thursday 13 August 2009

Locating American bean domestications

A couple of recent papers of the UC Davis crops sciences group, continue the research tradition of Paul Gepts in providing further refinements in out undrerstanding of Phaeseolus vulgaris domestications, especially in terms of locating these two domestications and identifying closed related wild popualations.

Kwak and Gepts published in Theoretical & Applied Genetics 118 [March 2009] an open access paper on a phylogenetic and population structure analysis on wild and domesticated beans, reinforcing earlier inferences of separate Mesoamerica and SOuth American origins.

Further details on the Mesomaerican wild populations, their relationships and distributions, can be found in another paper by Kwak, Kami and Gepts (2009) The Putative Mesoamerican Domestication Center of Phaseolus vulgaris Is Located in the Lerma-Santiago Basin of Mexico, Crop Science 49: 554-563. This study concludes that Mexican beans did not originate in the Rio Balsas valley favoured for maize origins--and supported by recent archaeobotany work, but elsewhere in Southwest Mexico. This was on the News feeds of the Crop Society of America last week.

Review on lentil domestication

A recent review article by Sonnante, Hammer and Pignone (2009) " From the cradle of agriculture a handful of lentils: History of domestication" in the rather obscure Rendiconti Lincei of April reviews the archaeology and genetics of Lentil domestication. It provides a useful overview, including a wide range of neutral genetic evidence that confers with the orthodoxy (e.g. of Zohary and Hopf) of a single Lentil domestication somewhere in the Levant, although the authors note the possibility that pre-domestication cultivation began with more than population of Lentils, but in the end only one was domesticated. They also provide a tabulation of the identified domestication-related genes in Lentil, which have generally received less attention than those in peas or Phaeseolus, and discussion of the morphological domestication syndrome in Lentils. They some speculation on why/how people came to cultivate lentils, which remains something of mystery for this and other pulses, in which seed germination rates of wild types are so low as to make them unlikely candidates for domestication. They concur the early Near Eastern agriculture including that of Lentils did not come from a dump-heap origin, but they still suggest that wild lentils might have occurred as weeds in early cereals and thus been a co-domesticate. Given what we know of wild lentil habitats this hypothesis seems little stronger than a dump-heap model, and I must favour some sort of intentional interest in Lentils and other pusles (perhaps for their protein content, or taste, or storability) which lead early cultivators to persist in their efforts despite initially low germination rates.

Thursday 6 August 2009

Rice genetics watch: SNPs confirm widespread hybridization events

Published in PNAS last week was another major genetic study rice genetic diveristy, phylogenetics and genome structure. The study lead of Ken McNally at IRRI, entitled "Genomewide SNP variation reveals relationships among landraces and modern varieties of rice" once again confirmed the wide divergence between indica and japonica, as well as the rather distinct and intermediate position of the aus group of rices, adpated to dry cultivation Bangaldesh and thereabouts. Their summary phylogeny illustrated this clearly:

The dataset set size, in terms of numbers of accessions is quite small (20 selected varieties), but that it made of for this is the large coverage of the genome and the detail of genome structure revealed by its focus on single point mutations (Single Neuclotide Polymorphisms or SNPs). They covered 3.6 million base-pairs of sequence and discovered nearly 160,000 SNPs! In all of this the deep divergence of indica and japonica, which must precede the beginnings of cultivation was indicated. Even if morphological domestication traits are shared (such as the reduced shattereing of the sh4 mutation, or the Prog1 gene for erect growth) this must be attributed to much more recent hybridization probable since the start of management/cultivation. I favour a hypothesis of the introduction of introduce domesticated japonica to the Ganges or Indus where hybridization took place with unimproved proto-indica cultivars. (A key distinction here is between cultivation and domestication). Such a hypothesis, which can explain the genetics of domesticated rices is at odds with claims for an early Holocene rice domestication in the Ganges, e.g. at Lahuradewa, which does not fit with the genetic make-up of modern indica. But such early and important hybridization events were probably not the last.

The key conclusion of this study is that this is evidence for a large degree of hybridization between the different domestic rice clades, i.e, between indica and japonica, and between these and aus. This is an important conclusion, as it means we can not consider the long-term history of these rice lineages as separate but rather we must see them as entangled. With these lineages crossed (intentionally or unintentionally) over the millennia of cultivation to produce a greater range of varieties and adaptations. This may seem obvious but many (most?) prehistories of rice paint extremely simplistic (and unrealistic) pictures, whether one takes common archaeological accounts such as single origins linked to Austronesian or Austroasiatic expansions, or one takes some recent geneticist just-so stories of decreasing 'primitiveness' of rice varieties as one move north or west from Island SE Asia as indicative of an early (and stealth) origin somewhere in the Islands from which Chinese rice derived (e.g. as postulated in the recent Izawa et al. paper).

We can look forward to some future unravelling of the complex, entangled history of rice spreads and hybridizations.

This study got some on-line publicity, e.g. on ScienceDaily, but which seems to have missed the key point about how major hybridization has been in the evolutionary history of rice!

Wednesday 5 August 2009

Where from the earliest Old World cotton?

I have received a recent query about early cotton in Nubia and South Asia, vis-a-vis the early occurrence of apparent cotton fibres in plaster from Dhuweila in Jordan (published by Betts et al 1994, J. Archaeological Science). This came in response to discussion of the find in the recent review I co-wrote with Nicole Boivin on the Holocene prehistory of Arabia (including several discussions of crops). I reproduce here my emailed reply as to why I have not committed on the possibility suggested by Betts (et al.) of a Nubia OR South Asian source. I have added links to references cited.

The Nubian source is based on reported cotton from Chalcolithic (A-Group) Nubia, first reported by Chowdhury & Buth in 1970 in Nature. The Indian Expedition to Nubia has preliminary reports on the archaeology in Indian Archaeology: A Review 1961-62 (which can be downloaded), and more extensively in Fouilles en Nubie (1961-1963). The A-Group Nubian cotton is problematic, with criticism published previously be me and by Zohary & Hopf. First it comes from goat dung, which does not necessarily indicate textile processing (admitted in the original Chowdhury publication). Second it comes from an undated excavation where it is alleged to be associated with A-Group ceramics (i.e. 3300-3100 BC-- mid-Third M. BC as cited by Betts [1994] is simply a mis-dating by the Indian archaeologists of 1962 who never got to grips with the Nubian sequence-- the dating of which was sorted out later, e.g. Trigger 1965; but especially Nordstrom 1972, Williams 1986; the region is largely depopulated at 2600 BC except for the Old Kingdom outpost at Buhen), but I am very worried that goat dung containing cotton seeds in Lower Nubia is more likely intrusive from later (Late Meroitic/Post-Meroitic) when cotton was known to be widely cultivated in the region. Stratigraphy in Nubia is always problematic. (I speak from experience in the 4th cataract), due to heavy deflation and reburial with windblown sand. For a published case-in-point consider Wadi Kubbaniya: Late Palaeolithic with charred wild plant remains AMS-dated to 16,000 bp and un-carbonized barley AMS'd at 500 bp [although not from the same excavation season] ! Things get mixed and the depth of deposit at Afyeh where it was found (the Indian Expedition to Nubia) was not very far beneath the surface. If it were from Nubia, how come there are no further cotton finds for 3000 years in the region? (Nevertheless, it would be nice to have more details about the Afyeh excavations, which remain largely unpublished and somewhere in the ASI archives in Delhi). I would note that Chowdhury also identified the Afyeh cotton as G. herbaceum based on a cross section of the seed coat. Perhaps this method works, but I have been unable to replicate it on the SEM (in modern material), which is a pity as it would be great to be able to track the two cotton species from archaeobotanical finds.

In addition, Naive African cotton, Gossypium herbaceum, is reported wild only much further south in Africa. It is of course possible it has gone extinct in Nubia, but if it were in 4th M. BC Nubia then it should on biogeographic grounds have been in Egypt too-- there is nothing in the Lower Nubian flora which is not in Egypt. (Is it likely the Egyptians would have overlooked using a species like this?). But, if one does postulate extinct wild Gossypium herbaceum as far north as Nubia then why not in mid-Holocene (wetter) Arabia as well?

Mehrgarh Period II has cotton seeds and fibres preserved in the earliest copper beads (Moulherat et al. 2004). On present evidence it seems the best, and only reasonable candidate. There can be presumed (but not proven) to come from Gossypium arboreum.

I must admit to remaining perplexed about the Dhuweila find. If textiles were traded long-distance one would not expect them to be valued, not used in tempering plaster. But perhaps this was not a common temper but a rare inclusion where someone tore a frayed tunic or something; the Dhuweila team got lucky-- one would need some systematic and quantitive approach to plaster temper to establish this.

My (obscure) article on Indian cotton and flax archaeology may be of some interest, as it reviews the archaeobotanical finds of these two species in India and Pakistan, with some notes on elsewhere [pdf]. For an updated review of cotton in Nubia see the chapter by Clapham and Rowley-Conwy in the recently published Hillman Feitschrit.

Monday 3 August 2009

Gordon Hillman honoured with Feitschrift

Yesterday, Gordon Hillman had some surprise visitors, Andy Fairbairn and Ehud Wiess (and I tagged along), who presented him with a feitschrift in his honour, published last week by Oxbow Books, Several years in writing, editing, and production the volume came as pleasant surprise to Gordon.

Gordon is pcitured here with the Feitschrift in his honour and the two editors, his former students Andy Fairbairn (University of Queensland) and Ehud Weiss (of Bar-Ilan University & the Weizmann Institute of Science). This book reflects the wide impact of Gordon's research, teaching and ideas both amongst colleagues (inlcuding junior colleagues like myself), but especially amongst his students, drawn from all over the world).

In typical fashion, Gordon offered us tea but suggested that first we ought to get out and collect some Deschampsia (D. caespitosa, the tufted hair-grass), as it was at the end of its ripening window (of less than 2 weeks or so). With his characteristic enthusiasm and eneregy we headed to Pevensey Marsh with baskets and seed beaters to have a short session at paddling up some spikelets from the extensive stand that grows in an under-grazed area of the marsh. (It has small red grains, not dissimilar from the Ethiopian crop tef in terms of size).
There was more time spent sitting and eating some fruit (foraged by Andy & Ehud from a supermarket) than actually collecting, with conversation taking up issues of harvesting windows for wild grasses, acorn gathering, processing and tree ownership, seaweed collection and Australian Auracaria pinecones. Having caught up we headed back to Gordon's kitchen to dehusk and grind some Deschampsia and Festuca he had gathered earler in the week and dried. And some simple wild grass biscuits were griddle cooked to accompany our cup of tea.

It is inspiring to see Gordon still add it, regularly out in field and forest, gathering, experimenting with processing and eating. And, he is still working on a book that gathers all of this knowledge and experience on wild food plants together.

The feitschrift contents have been presented previously on this blog. The book can be ordered from Oxbow Books. A full tally of Gordon's published works (so far) can be found here.

Saturday 1 August 2009

Parallel origins: true modern human lithics in India (as true for agriculture)

The latest publication from the Petraglia & Korisettar palaeolithic research team, working in South India, was published last week in PNAS—Population increase and environmental deterioration correspond with microlithic innovations in South Asia ca. 35,000 years ago. This study dovetails nicely with recent simulation modelling effort of some UCL colleagues (Adam Powell, Mark Thomas, and Stephen Shennan, director of the Institute of Archaeology), published in Science last month. (The appearance of these two papers close together is entirely coincidental). This simulations suggest that behavioural innovations, such as modern human behaviour, should be expected to emerge when circumstances are right (especially due to demographic factors of higher interactoing populations), and to be maintained only if demographic circumstances permit (and therefore disappear if populations decline).

These two studies together represent importance counters of an orthodoxy that sees ‘modern’ behaviour as emerging once, and therefore being a great invention when hard cognitive architecture came into place, perhaps even driven by a key genetic mutation for intelligence. Such is the orthodoxy implied by classic textbooks on human evolution, such as by Richard Klein (at least as was used when I was a student) or the recent reviews by Paul Mellars (e.g. his Science paper of 2006). In this view modern humans, heir cognitive abilities and the behavioural application of those abilities emerged once (in Africa) and spread out of Africa (once) to bring intelligent modern everywhere else (perhaps at sometime between 60,000 and 40,000—depending on whether one prefers to emphasize the earliest possible dates for Australia or the Upper Palaeolithic transition in Europe). The evidence from South Asia shows clearly that toolkits were middle Palaeolithic (and in this sense not ‘modern’) from >75,000 to 35,000 years ago, and yet genetics suggests that these would have been anatomically modern humans (and they must have moved through South Asia earlier than their arrival in Australia sometime between 60,000 and 50,000). The bottom line is there is a good evidential case to be made, congruent with the modelling of Powell et al., that the cognitive architecture for modern behaviour was around but the innovations that we regard as ‘modern’ emerged when social and environmental circumstances demanded.

There is a parallel here to where thinking on agricultural origins is moving. There has long been an orthodoxy that agriculture was a great and rare invention, and that agriculture came to most regions by the migration of farmers from a few centres of the influence of a good idea. In the more extreme cases, only 3 centres of origin (Mexico, Near East and China) are accepted. But the evidence of archaeobotany—where it is available—combined with the biography of wild progenitors, and where avail able the genetics of crops/livestock, suggest that there was many more centres in which societies converged on agriculture—the behavioural changes towards manipulation of the environment in favour of the reproduction of a few food species (domestication, the genetic sense, was an unintended consequence of these behavioural shifts, when the genetics of the species allowed). In my most recent attempt to sift through the combined data, I concluded that there is strong case for 24 separate instances of agricultural origins globally—although as many of these are poorly documented and geographically close together one might reduce this to 13, as per the map below from Purugganan & Fuller:

The point is that agriculture, like modern human behaviour, was not a one time great invention, but the product of social and environmental circumstances to which human groups with the same cognitive potential responded in parallel ways. The question in both cases is: what were the common denominators of those circumstances?

Friday 31 July 2009

New e-volume on the origins & spread of bananas

Just published is a special issue of the on-line, open access journal Ethnobotany Research and Applications, devoted to the "History of Banana Domestication". For those unfamiliar with the journal, it is worth watching, as it publishes a wide range of ethnobotanical papers, including several that have been relevant to studying crop origins and traditions of use. The journal is free, after one registers, and articles can be downloaed as PDF. This special banana issue arrises from a session at the Dublin World Archaeological congress. It starts on page 163 of Volume 7.

The contents are as follows:
Special Issue: History of Banana Domestication
Why Bananas Matter: An introduction to the history of banana domestication...Edmond De Langhe, Luc Vrydaghs, Pierre de Maret, Xavier Perrier, Tim Denham [link to this abstract]
Bananas and People in the Homeland of Genus Musa: Not just pretty fruit...Jean Kennedy
Combining Biological Approaches to Shed Light on the Evolution of Edible Bananas...Xavier Perrier
Differentiating the Volcaniform Phytoliths of Bananas: Musa acuminate...Luc Vrydaghs, Terry Ball, H. Volkaert, Ines van den Houwe, J. Manwaring, Edmond De Langhe
Relevance of Banana Seeds in Archaeology...Edmond De Langhe
Impressions of Banana Pseudostem in Iron Slag from Eastern Africa...Louise Iles
Banana (Musa spp.) Domestication in the Asia-Pacific Region: Linguistic and archaeobotanical perspectives...Mark Donohue & Tim Denham
Banana Cultivation in South Asia and East Asia: A review of the evidence from archaeology and linguistics...Dorian Q. Fuller & Marco Madella [download pdf]
Early Bananas in Africa: The state of the art...Katharina Neumann & Elisabeth Hildebrand
Bananas and Plantains in Africa: Re-interpreting the linguistic evidence...Roger Blench

Tuesday 30 June 2009

Rice genetics watch

A few notes on three recent additions to the library of publications of rice genetics.

1. Yamamoto et al (from Tusukuba) have publiished a review "Towards the Understanding of Complex Traits in Rice: Substantially or Superficially?" in DNA Research. This seems to be aimed at breeders and the potential of marker-assisted breeding, but it contains a useful compilation on a good range of QTLs for various domestication-related and post-domestication traits. It includes a schematic map with ~4000 qtls mapped onto the 12 chromosomes of rice, which just goes to show both how much information there is on rice, and how complex it is to understand the history of this crop when there is so much information. It is fair enough to say that most reviews have an inevitably partial view of evidence from the rice genome.

2. Panuad has published a short essay, ostensibly in honour of Darwin, on "The molecular bases of cereal domestication and the history of rice" in the French journal C. R. Biologies.It strikes me as neither particularly insightful nor up-to-date, but it is short and might of interest the less rice-savvy. Its limited reference to archaeology is rather disappointing and odd (a single Chinese article in the minor journal Nongye Kaogu), and the claim that we have less evidence from India as opposed to China because preservation is worse in tropics, is not really a fair assessment. True charred seed densities tend to be lower in India than China, but the main reason is that more Neolithic sites have been excavated in the Yangtze than in the Ganges. And even though flotation was started in India in the 1970s, perhaps 20years ahead of China, it is now being widely practiced in China as a rapid rate, whereas it is the the same 2 two labs doing flotation and analyses in India that started it in the 1970s (plus a couple of us occasional foreign visitors). Indian needs more sampling, and not to be written off as too tropical to work i, but needs more work, more workers, and more critical analysis and debate (e.g. about the nature of Lahuradewa's early rice).

3. The recent genetics paper I have seen that I am most impressed with is the study by Yamane et al (2009, in Rice) of the phylogenegentics of Hd6, one of the genes involved in regulating heading (flowering), and linked to response to photoperiod (daylength). It is clear that non-responsive plants have one of two alternate forms of the responsive (short-day) type, corresponding to two indica vs. japonica domestication pathways. It also suggests that a non-reponsive type found mainly in temperate japonica rices also derives from the wild and is found in some South Chinese wild rices. This story is entirely reminiscent of the case in barley recently brought to light by Huw Jones and colleagues.

Monday 29 June 2009

Hunter-gatherers, farmers, and monumental storage

Just a quick note of record of a new edited volume Interactions between Hunter-Gatherers and Farmers: from Prehistory to Present, edited by Ikeya, Ogawa and Mitchaell, was recently published in the series Senri Ethnological Studies by the National Museum of Ethnology in Osaka [at the time blogging, this was not yet listed on their website]. The book is entirely in English, ands arises from a session at the WAC intercongress held in Japan in 2006. It includes a mix of studies from ethnographic (2 chapters on the Agta of the Philippines, and 2 chapters on Homng farmers and Mlabari (former) hunter-gatherers in northern Thailand) and archaeological (one on Southern African by Peter Mitchell, one on the spread of farming to Guangxi, China by Tracey Lu, and 3 on Japan, and one on the archaeology of Northeastern Luzon, Philippines, exploring the long-term development of a frontier of interaction between farmers and hunter-gatherers.

I certainly haven't read all of it yet, but I would note that the short chapter on Guangxi by Lu provides a useful brief overview of the Chronology of the main excavated Neolithic sites in southwest China, the evidence for rice, millets and foraging. The Chapter by Takahashi on interdependent relationships between late Jomon 'foragers' and Yayoi paddy farmers, provides some useful material including an updated map of some 29 sites with preserved paddyfield systems dating to this period. At the centre of the book is a nearly 100-page chapter by Leo Hosoya on the symbolism of grain stores and the emergence of hierarchy in the Yayoi period, with reference to artistic evidence, settlement plan, and crop-processing (from rice grains and spikelet bases), stone harvest knives, octopus traps, and more. A rich tapestry with much to digest and much that is suggestive of the potential role of monumentalization of storage in creation of a new kind of settled community-- perhaps there are some fruitful comparisons to be made to those first permanent granaries recently found in PPNA Jordan (blogged last week).

Nubia as world centre, c. 1900-1600 BC (and a note on millet)

In the latest Norwegian Archaeological Review Hafsaas-Tsakos argues for seeing archaeological Kerma, what the Middle Kingdom Egyptians referred to as Kush, as shifting from a 'periphery' to a 'centre' in the world system at that time. (This article is not a particularly botanical one, but Nubia is always close to my heart, so how can I pass up a note on it.... for a botanical side to this note, read on). This argument is one that needs to be made, again (it has been made before by Stuart Tyson Smith). Kerma was probably the largest city in the Nile valley at its heyday (1700-1560 BC), and one of the great world cities at that time (particularly as the cities of the Indus and the Oxus had pretty much withered away by this date). The importance of Kerma a few centuries earlier is indicated by the large scale, and heavily fortified Egyptian military presence at the Second Cataract, indicated by the many Egyptian fortresses and their garrisons of the Middle Kingdom (this article includes a nice photo of one of the last, unsubmerged fortresses of Nubia at Shelfak). It seems odd that the author of this paper opines that the Egyptian presence was just about trade and did not involve control of Lower Nubia, as military towns and inscription attest to garrisons patrolling swathes of Lower Nubia (see, e.g. Joe Wegner's article in JARCE 32 (1995) 127-160)-- presumably to keep the natives in line and assure supply lines to and from Egypt. As is so often the case, economic administration and military control went hand-in-hand.

Unfortunately, this article says little about what commodities flowed from Kerma northward to make it such a centre, or what flowed from Kerma's periphery to Kerma. The importance of gold sources in the Third Cataract to Second Cataract stretch of the Nile and the Red Sea hills to the east are well-known, but I would like to flag some plant resources, of course. In her list of possible commodities, the authors notes incense. The importance of incense should be underscored. Incense was central to Egyptian temple ritual, its smoke literally helped to feed (and communicate with) the gods; and it was a required in the embalming of royal mummies. One of the forms of incense of 'ntyw, was likely frankincense or myrhh or a collective term for both. Egyptian sources indicate that this often came from the mysterious land of Punt but also flowed from Nubia. But the sources of true Frankincense (Boswellia) and myrrh (Commiphora) lie far away in Yemen, southern Oman and Somalia. Nubia was one of the point of contact then with poorly understand trades links to much further away. This centrality of incense goes back to the very beginnings of Egyptian written record, and probably before, even to the Predynastic period (see, e.g. some discussion in the recent book by David Wengrow). More than half a century ago, Henri Frankfort (The Birth of Civilization in the Ancient Near East) drew attention to the importance of incense to both early Egypt and Mesopotamia and he even speculated that traders from the two societies might have met and exchanged ideas of kingship and culture in the incense ports of Yemen-- rather a fantasy, but the importance of distantly imported incense is clear.

Hafsaas-Tsakos illustrates an imported Near Eastern juglet that probably contained fragrant olive oil or the like from a grave at Kerma period Ukma. The excavations at Ukma, published in the 1980s, provide the other tantalizing clue to Kerma's links to cultures to the east: finds of broomcorn millet (Panicum miliaceum), identified by the archaeobotanist Van Zeist (his short report in English on 'The Plant Remains' can be found in the french monograph by Vila). The importance of this lies in the fact that this species is absent from Egypt, the Levant and Mesopotamia at this time. This crop appeared in the Indus valley in the Late Harappan period, after 2000 BC (as part of a larger group of Chinese imports, see pg. 36 in my J. World Prehistory paper of 2006). There are possibly earlier finds of the mid-late Third Millennium BC reported from Yemen and eastern Iran (Tepe Yahya). Other Third Millennium find comes from further north in Central Asia. It is well-known that some African crops moved east, via sea, to India by, or just after 2000 BC; Panicum miliaceum is the one crop for which we have evidence that it moved the other way, in the world of Kerma/ Kush.

Hafsaas-Tsakos is right to put Kerma on the map of a Bronze Age world system, but such an expansion of the map needs to also include areas upstream that linked the upper Nile to Eritrea, Northern Ethiopia and the Red Sea, with its ties to the incense lands of Yemen and Dhofar. The millet from Kerma-age Ukma is the forensic clue that there were contacts, even if via down the line trade, between Kerma and these cultures to the East and South, in Yemen and to the Indo-Iranian region beyond (and from there ultimately to China where this Panicum crop originated (on its origins, see previous posts on Dadiwan and Cishan). Kerma was another centre but part of its importance lies in its links to these poorly-studied, maritime 'peripheries,' which in their own right were central to the flow of key-valued resources (like incense) with which new cultigens piggy-backed.

For more on the history & archaeology of Nubia, try this site from the expert Dr. David Edwards.

For a googlemap of many sites in Nubia, including Kerma (which you can see if you zoom in), try here.

Thursday 25 June 2009

Indian Archaeobotany watch: Lahuradewa 2008

Critical comments on the archaeobotany of Lahuradewa. The Pragdhara volume 18 (for 2008) arrived in London in the first week of June. It constitutes a special issue on the Neolithic and agricultural origins, with various reviews on other parts of the world (some I was involved in writing), and for various parts of South Asia. Perhaps the centrepiece of the issue is the latest report on Lahuradewa, excavated by the Uttar Pradesh State Department of Archaeology, directed by Rakesh Tewari. This one article from the latest Pragdhara has been made available on-line here. I have been a disbeliever in print in the past on the rice from this site (see JWP 2006, and others). Not about whether it is an important site, nor the fact that it has the earliest finds of rice from South Asia (>6000 BC), nor the earliest pottery in South Asia-- demonstrably earlier than Mehrgarh Period 2, which starts from ca. 6000 BC. But I do not think, and I now doubt even more, that the rice was domesticated. It is not even clear that it was cultivated, and is plausibly (perhaps safest interepreted as) wild gathered.

They report three new radiocarbon dates on bulk charcoal samples, which calibrate to between 8000 and 9000 BC. This means that the 50cm or so of cultural stratigraphy now has to account for 5000 years, or more, of human occupation. One has to conclude that this occupation was unlikely to have been permanent and sedentary. Importantly, they also recovered more plant remains, including more rice from the lower levels (Period 1A). Details of numbers, densities and samples from flotation are not reported. New finds also include a large ceramic fragment tempered with rice husk, and apparently some rice grains, as well as carbonized grains and spikelets. They suggest that these are domesticated on the basis of three criteria, grain size and grain ratios (using what might be termed the ‘Vishnu-Mittre index’), husk patterns, and the alleged presence of non-shattering rachises (i.e. spikelet bases).

Spikelet bases. Lets start with the last observation first.

Clear criteria for distinguishing three categories of spikelet bases, one of which is definitely of domesticated type, have been recently published (Fuller et al. Science 2009; Fuller & Qin 2008), although these publications probably post-date when this report went to press. Nevertheless, earlier work by Gill Thompson (1996; 1997) provided clear illustration of the differences between typical wild and typical domesticated spikelet bases. There are four spikelet bases shown in their Figure 16, one which is shown in close-up (Fig 16.3: above) as an example of the non-shattering type. Its long rachilla is still attached, which is a trait occassionally (but rarely!) encountered in domesticated rice, and when it does occur it usual in East Asia rices that possess multiple non-shattering alleles and it seems most common in modern varieties adapted to machine harvesting. Rather the attached rachilla is typical of rice harvested immature and green. As noted in the Lower Yangzte and China generally, spikelet bases with protruding rachillae are common in the earlier Neolithic (e.g. at Kuahuqiao and Tianluoshan) but these forms decrease over time (see Fuller et al Science 2009 [follow the link from here]), until by ca. 2000 BC in Chinese sites they are very rare (<10%).

It should be noted that both of these represent spikelets that do not appear to have broken during dehusking, and that appear thin and deformed, and are likely immature (green spikelets), which did not contain fully-formed grains. These therefore look more like green-harvested, wild rice spikelets than the threshed remains of a domestic rice harvest! But these are illustrated as the best candidates of Lahuadewa "domesticates". What is more they both have preserved awn bases. While the loss of awns is not a definitive trait of domesticated rice (many varieties, especially of tropical japonica) are awned, the presence of awns is typical of wild rices. The pictures therefore do not agree with what is stated in the text, but quite the opposite.

What about husk patterns? The basis of using husk patterns to distinguish definitively between O. nivara, O. rufipogon and O. sativa has never been clearly demonstrated or published. Quite the contrary this seems to be a non-replicable, subjective judgement. The idea is that domesticated rice is nicely ordered with square cells, and wild rice is wild and disordered. There is perhaps more of the magic of metaphors than a real method here I suspect—in any case I have never been able to see this, and one can find exceptions to this in evefy box of wild or domesticated reference material. The original inspiration of this came from the work of T. T. Chang (and was then developed by Vishnu-Mittre and his students in Lucknow), and although Chang often assigned archaeological material on the basis of husk patterns, this relied on a kind of personal magic and authority and had always had to be taken on faith. Chang borrowed this method (which was termed the SUMP method-- Susuki’s Universal Micro-Printing) from the earlier work of Katayama (1969). In the original study it is determined that there are no significant differences among the species of the sativa-complex (including rufipogon) but only between these and other wild rices (non-AA genomes rices). [Katayama, T, 1969. Botanical studies in the genus Oryza I. Morphological and anatomical investigation of glume- and leaf surface with the SUMP and histological method. Memoirs of the Faculty of Agriculture Kagoshima University 7/1, 89-117.]

I suspect that there may be some tendencies of difference between wild and domesticated spikelets husks on a popualtional level, akin to the weak tendencies in husk phytolith form, all of which are probably linked to selection for larger, fatter grains. The husk patterns therefore should show trends of gradual change overtime as grains do, but until methods of measuring and quantifying this over time are developed, this is a non-method, and seems a leap of faith too far.

Grains. This report provides a table of grain measurements, on 26 grains (although judging by the photos I wonder if some of this included attached husk, which would elevate some measures and create greater variance). It should be noted that these are all Period 1A grains with no comparison provided to later periods. Thus there is no possibility of looking for the temporal trends that one expects with domestication. In any case it is clear from examining these measurements that they break into two size groups, one is small and the other larger. This is easily illustrated in the following chart.

The smaller-grained group is comparable to non-sativa small-grained rices (e.g. O. officinalis), while the other falls into a size range that could be domesticated rice. However, when length and width measurements are taken as a scatter plot, all of these grains fall within the range defined by modern O. rufipogon and (especially) O. nivara. None of them fall into the range of domesticated rice. In order words none of them is bigger than a baseline that might be defined on the basis of modern measurements. Both the large and small groups contain ‘Vishnu-Mittre indices’ that are >2 and ~1.7, which are alleged to distinguish domesticated and wild rices. Internally this data deconstructs the usefulness of this index as a marker of domestication. Modern measurements on populations of wild domesticated rice grains certainly do not bear these indices out!

The two populations are illustrated also by scatter plot, below, where the Lahuradeva specimens (light green) are plotted over the scatter of modern populations that were plotted in Fuller et al (2007, Antiqiuty; measurements by Emma Harvey). To compare the modern and ancient grains I have added a +10% increase to the archaeological specimens as a reasonable standard correction for charring. It can be seen that the Lahuradewa grains plots nicely with Oryza nivara, while the shorter grains plot with O. granulata and O. officinalis.

Because comparison with modern rice grains may be complicated by the charring factor, I have taken two archaeological populations from India for comparison as well. Both are Early Historic (perhaps ca. 200 BC, or so) and both come from regions beyond the range of wild rice. One is from a lense of charred grains at Terr, Maharashtra, and the other is from Balathal, Rajasthan. Both were measured in London, 300 grains each. As can be seen there is considerable variation (part of that is probably due to the fact that the Balathal grains were charred as grains, whereas the Terr grains were charred as spikelets and many retain husk fragments), but these later Indian archaeological domesticated rices are clearly shifted away from the range of reference nivara and from Lahuradewa. Thus, using later archaeological rices as a baseline the larger Lahuradewa grains do not look domesticated. There is nothing beyond reasonable doubt to accuse these grains of being domesticated.

Interestingly, if these grains are compared to those from the later Neolithic in the Ganges, e.g. measured grains from Mahagara and Koldihwa, they fit nicely together. Based on recent spikelet base finds from Mahagara (1800-1600 BC), we know this rice to be domesticated. This then implies that there has been no appreciable change in grain size in rice the middle Ganges between ca. 6000 BC and ca. 1800 BC, despste being domesticated by the end of this period. This implies a very different domestication process than that in Chinese rice, in which grains get progressively larger over time as spikelet bases become non-shattering, or from wheat and barley in the Near East (see my Annals of Botany 2007 paper). Indeed, it suggests that there was hardly any selection for increasing grain size in the proto-indica cultivated in the Ganges plains (whenever cultivation began, which remains unclear). This makes sense in terms of hypothesized patterns of wild rice exploitation and minimalist wild plant food production (pre-domestication) cultivation that can be postulated for the Ganges (Fuller & Qin 2009).

This evidence is probably to be expected, given that genetic evidence indicates that several key mutations had to be introduced to proto-indica via hybridization from domesticated japonica, including sh4, for non-shattering, prog1 for erect growth habit, as well as rc for white pericarp. The real leap forward for indica rice was perhaps closer to 2000-1800 BC. Nevertheless the roots of rice cultivation were laid down earlier, but it remains unclear if this was as early of the eariest dates at Lahuradewa or whether these were periodic seasonal rice gatherers.

Diatoms. It is also suggested that the diatom assemblage from the lake sediments indicates rice growing fields. Are they suggesting, implausibly, paddy fields at this date? There is simply too little background work on the ecology of diatoms in natural wetlands where Oryza nivara, O. officinalis, etc, grow to be able to justify this statement. The diatom species that now inhabit rice fields existed before there were rice fields, and they had to come from somewhere. The habitat of wild rices seems the obvious place.

(Appendix) Some general notes on the plant assemblage. Plant taxa reported from Period 1A are: rice (reported as wild and domesticated, but see below), wild Setaria (referred to yellow foxtail millet, S. pumila), Chenopodium (referred to C. album), Coix lachryma-jobi, Artemisia sp., Silene conoidea. The Silene appear to have intact light-coloured hila (Fig. 6.8), which makes one a little concerned that they may be uncharred and intrusive, but maybe not. The rice grains as illustrated are for the most part plump and appear mature, but they are relatively short (more a feature of O. nivara than typical modrn indica), except for a few elongate, thinner grains (Fig. 6.5), at least one of which is poorly formed, which are referred to O. rufipogon; indeed they are quite plausibly rufipogon, but may also include immature grains.

Period 1B (probably 2500-2000 BC, although one wood charcoal date goes back to ca. 2800/2900 BC): apart from rice, finds include free-threshing wheat, barley, lentil, Cyperus, Coix lachryma-jobi, Artemisia, Setaria cf. pumila [Saraswat persists in the use of S. glauca, a taxonomically illegitimate name—Linnaeus’ type specimen was pearl millet not yellow foxtail!-- but lets not squabble], kodo millet (Paspalum scrobiculatum)—these are in the husk and look more likely to be wild/weedy specimens rather then the crop. The rice includes many grains referred to Oryza sativa (reasonable), some O. rufipogon (which again look like they may include immature grains: Fig. 8.8), and some O. officinalis (very short and wide), with length of ~3mm or less (Fig. 8.9). It’s a pity that these and the sativa type grains were not measured for comparison to the Period 1A material. Impressively there is some husk material of O. officinalis. This adds another site to evidence for the exploitation (or at least harvesting) of more than one rice species in the Ganges plain. Emma Harvey (in her PhD, UCL, 2006), at Mahagara and Koldihwa, Neolithic sites of the Second Millennium BC, measured husk phytoliths (the double-peaked morphotypes) and found a small proportion of husk phytoliths that fell well outside of the range of the sativa-rufipogon complex, some of which overlapped reference measurements for O. officinalis. This suggests that we should expect multiple rice species to occur on many early sites in this region.