Early Neolithic cereal exploitation in Southwest Asia : gathering or cultivation?

The first step towards the adoption of farming in the Near East was the taking into cultivation of wild plants, cereals in particular. The majority of villages dating to the end of the Pleistocene/beginning of the Holocene have produced charred wild cereals. Here I will examine what we know with regard to their exploitation by attempting to answer five basic questions. This contribution stems from the following publications (Willcox; 2024; Willcox & Stordeur, 2013; Willcox et al., 2008) which can be accessed at: https://www.willcoxpages.fr

Were wild cereals taken into cultivation in a single core area and then the practice diffused, or were they adopted independently in different areas of southwest Asia?

Discoveries of early Neolithic wild cereal exploitation have been reported for PPNA and early PPNB sites (Fig. 1) from the Zagros to central Anatolia, from the northern to the southern Levant and in Cyprus. These finds demonstrate that the varieties of emmer and einkorn wheats and their proportions compared to barley and rye reflect the distribution of local populations of wild cereals. The geographical distribution of different cereals exploited during the PPNA and early PPNB corresponds to distinct cultural areas (for example Douché & Willcox, 2018). By the Middle PPNB, emmer in the southern Levant, einkorn in southeast Anatolia and separate varieties of emmer in central Anatolia and the Zagros developed non-shattering ears, indicating that cereals were taken into cultivation independently in different regions of southwest Asia and that these regions correspond to cultural areas, contradicting Gopher’s (2024) arguments for a single core area. However, later during the Middle PPNB emmer wheat became dominant in many regions, which suggests that this species was deliberately chosen over einkorn probably because it had better yield and was easier to process.

The initial sowing of wild cereals in some cases may have been sparked by imitation. During experimental cultivation of wild einkorn (Fig. 2; Willcox, 2024), involuntary sowing was regularly observed when harvests being transported to the processing area resulted in the spillage of spikelets which germinated the following year. Cereal gatherers throughout the Near East from the Natufian onwards must have witnessed such involuntary sowing, which may have seeded the idea to intentionally disperse wild cereals beyond their natural habitats.

Could early Neolithic cultivators have consciously selected for non-shattering cereals?

Conscious selection for populations with non-shattering ears can be carried out in two ways: (a) Pure or single-line selection, this was not developed until the early 19th century. Single-line selection necessitates isolating the chosen line from the main population. It has the disadvantage of drastically reducing genetic diversity. Isolating a single line from the rest of the crop would have been problematic (b) Mass or recurrent selection: this is the only method known to have been used by subsistence farmers. It involves regularly choosing grains from plants with desired characteristics for the next generation. They must make up a certain proportion of the population (hence mass selection) in order to have a viable crop. The advantage is that plants do not need to be isolated. Mass selection requires three prerequisites:

  • (1) that the trait can be readily recognized in the phenotype,
  • (2) that the trait has a high degree of heritability and is not the result of phenotypic plasticity
  • and (3) that it is desirable.

For a trait such as glume color in einkorn, the three prerequisites are fulfilled. For increased grain size, prerequisite 2 would not be fulfilled because grain size depends mainly on phenotypic plasticity. Mass selection for plants with non-shattering ears would be problematical because prerequisite 1 would not be fulfilled, this trait being difficult to recognize, first because harvests would occur before shattering, second because delayed ripening is common, some ears remaining intact longer than others, only to shatter when dehusked. Prerequisite 3 would not be fulfilled because without having experienced a population of non-shattering ears, cultivators could not know that it was a possibility, or that it was desirable. If mass selection was attempted for non-shattering ears, a certain proportion of plants with this trait must already have been present in the population, so natural selection would have already begun and would initially have outperformed conscious selection. Finally, early cultivators may not have appreciated that a trait could be inherited. For references and more details see Willcox (2024).

Once cultivation of wild cereals began, how many generations were needed for shattering spikelets to be replaced by non-shattering spikelets?

Hillman and Davies (1990) and Zohary and Hopf (2000) argued that under cultivation einkorn with shattering ears would be eliminated within a dozen or up to 200 generations by natural selection. Tanno & Willcox (2006) argued that because crops were made up of mixtures of shattering and non-shattering spikelets at some Early and Middle PPNB sites, such as Halula, selection rates were low and that the selection took up to or more than a millennium. In more recent publications I have questioned my original interpretation, pointing out that the mixtures were not necessarily related to selection rates and could be the result of (a) complementary harvests from wild stands, (b) the presence of weedy varieties which have both shattering and non-shattering spikelets on the same ear and (c) identification bias possibly affecting the proportions. The proportions differ irregularly from site to site throughout the region, which may reflect different causes mentioned above. Thus the time taken for shattering populations to be replaced by non-shattering ones may vary greatly from site to site and area to area depending on the methods of sowing and harvesting. So can we still talk about the slow millennial road to domestication (Allaby et al., 2022)? Yes, but with reference to the transition to mixed farming over the entire region of Southwest Asia.

Finally, genetic input from wild populations with shattering ears would have occurred at sites situated near wild cereal stands (despite high levels of self-fertilisation). This input would provide genetic variability allowing cereals to evolve independently in different regions (Fig. 3).

Is it possible to know whether cereals with shattering spikelets found on archaeological sites were gathered from the wild or harvested from arable plots?

The quantities of charred remains and the archaeological evidence leave no doubt that cereals and pulses were the dominant plant food resources during the PPNA in northern Syria (Willcox & Stordeur, 2012). Circumstantial evidence for the cultivation of wild progenitors (Willcox et al., 2008) was posited on the basis of seven lines of evidence at PPNA Jerf el Ahmar and Early PPNB Dja’de (Fig. 4):

  • (1) the location of sites far from wild einkorn and rye habitats;
  • (2) a reduction in gathered edible seeds of non-founder plants compared to an increase in founder crops;
  • (3) an increase in the grain size of cereals, possibly due to enhanced growing conditions;
  • (4) large-scale cereal-processing installations (Fig. 5);
  • (5) an increase in potential arable weed taxa;
  • (6) evidence for extensive rodent activity, in particular the house mouse (Fig. 6);
  • (7) the ubiquitous use of cereal chaff as tempering material in building earth (Fig. 6).

Individually these lines of evidence do not demonstrate that cultivation (which entails the sowing of seed) was being practiced; however, taken together they certainly correspond to large-scale cereal exploitation. Many of the above features have been found on PPNA sites, for example Göbekli (Dietrich et al., 2019), Tell ‘Abr, Mureybet, El-Hemmeh, Netiv Hagdud. Whether this indicates exploitation of wild stands or cultivation or both is difficult to disentangle. On the one hand continuous systematic cultivation at Jerf el Ahmar during the 500 years or more of occupation is improbable, because if this was the case, we should expect to see the appearance of non-shattering ears. On the other hand continuous gathering might have led to over exploitation.

The strongest argument for cultivation of wild cereals at Jerf el Ahmar and neighboring PPNA sites including Tell Qaramel was based on observations that earlier sites with abundant cereal remains such as Epi-Palaeolithic Ohalo II and Natufian Dederiyeh and Abu Hureyra had very few potential weeds. In contrast PPNA sites had many more arable weeds analogous to Middle PPNB and later farming sites. A scenario to explain this increase might be as follows; the progenitor weed species were taken into cultivation perhaps with harvests from wild stands. They would have been pre-adapted to tilling, thriving in loose, open arable soils where they could proliferate. Weeds compete with crops for water, light and nutrients, hence it is important to control them. Early cultivators may have attempted to reduce weeds by weeding fields and by cleaning crops during processing. Disposing of weeds may have involved burning them, increasing the likelihood of weeds becoming part of the charred assemblage.

To differentiate between arable habitats and wild cereal habitats Weide et al. (2022) applied functional trait analysis using flowering duration despite its phenotypic plasticity. The authors chose 19 taxa identified from charred seed remains recovered from PPNA Jerf el Ahmar and Early PPNB Dja’de. They assumed that the 19 taxa came from crop-processing residues, but this is by no means certain because the sediments from which the samples were taken come from contexts such as building rubble, ash layers, pits and middens. In addition the samples contained other charred remains (not mentioned by the authors) such as charcoal, fragments of edible nuts and other remains from various habitats (for a critical assessment see Willcox 2023). Thus the chosen taxa may not have been crop-processing residues and may have come from local habitats where they still grow today (Fig. 4).

Jerf el Ahmar and Dja’de have been referred to as type-sites (Weide et al., 2022) for the cultivation of wild cereals. These sites were some of the first to propose cultivation of wild cereals but caution is required. First, because the charred seed remains do not provide a reliable differentiation between harvests from cultivated plots and those gathered from wild stands. Second, gathering and cultivation may have occurred concurrently and different combinations of modes of gathering, harvesting, sowing and tilling may have gone into and out of use during the long occupations at these sites.

How were wild cereals harvested, sown and processed?

Experimental planting, harvesting and processing of wild einkorn (Fig. 2) in addition to archaeological evidence (Maeda et al., 2016; Willcox, 2024) demonstrate that: (1) harvesting of not fully ripe cereals (Fig. 7) with minimal shattering (Fig. 8) using hafted flint blades was probably the method for both wild stands and sown plots during the Natufian and PPNA; (2) despite the early harvest the seeds could be sown the following year to produce a viable population as demonstrated experimentally (Willcox, 2024, table 1) ; (3) in the case of cultivated plots, shattering before or during the harvest would result in regeneration the following year without replanting. However, yields would rapidly diminish, implying that annual sowing would be necessary to maintain the crop (Willcox, 2024, tables 2 and 3); (4) annual harvests in the same area of wild stands would lead to depletion.

In conclusion, recognizing cultivation of wild cereals is problematic. Charred remains from PPNA sites tend to provide fragmentary and disconnected information, due to the nature of the sediments, imprecise identifications of charred seeds and taphonomic processes. It is possible that during the PPNA and PPNB at Jerf el Ahmar and Dja’de, seeds of wild lentils and/or cereals from wild stands were sown, but sowing may have been occasional, unsystematic and possibly used for specific crops. By the Middle PPNB it is clear that cereals were taken into cultivation independently in different regions of southwest Asia at different dates and evolved through natural selection. Only systematic annual re-sowing of seeds obtained from tilled plots would allow for selection of non-shattering plants, which appear during the Early PPNB and the Middle PPNB depending on the region. Shattering types persisted either as weeds or from supplementary wild harvests. Finally, I have avoided using the word domestication because I believe that it oversimplifies the complex pathways which led to the slow adoption of mixed farming independently in different regions. If domestication is considered to be the selection of favorable traits under arable conditions, then it is, in the case of Near Eastern cereals, an unintentional by-product of societies who tilled, harvested and sowed.

References

Allaby, R.G., Stevens, C.J., Kistler, L., Fuller, D.Q. 2022. Emerging evidence of plant domestication as a landscape-level process. Trends Ecol Evol 37:268–279

Dietrich, L., Meister, J., Dietrich, O., Notroff, J., Kiep, J., Heeb, J., Beuger, A., Schütt, B. 2019. Cereal processing at early neolithic Göbekli Tepe, southeastern Turkey. PLoS ONE 14: e0, 215,214. https://doi.org/10.1371/journal.pone.0215214

Douché, C., Willcox, G., 2018 New archaeobotanical data from the early Neolithic sites of Dja’de El-Mughara and Tell Aswad (Syria): a comparison between the Northern and the Southern Levant. Paléorient 44:45–57

Gopher, A. 2024. Time to Go Beyond Chrono-Stratigraphy: The (EPPNB) Aswadian Culture of the Southern Levant. Paléorient, 49-2 https://doi.org/10.4000/paleorient.3712

Hillman G, Davies S (1990) Measured domestication rates in wild wheats and barley under primitive cultivation, and their archaeological implications. J World Prehistory 4:157–219

Kerbe J.1987 Climat, hydrologie et aménagements hydro-agricoles de Syrie. Presses Universitaires de Bordeaux, Université de Bordeaux III, Talence.

Maeda, O., Lucas, L., Silva, F,. Tanno, K., Fuller, D.Q. 2016. Narrowing the harvest: increasing sickle investment and the rise of domesticated cereal agriculture in the fertile crescent. Quat Sci Rev 145:226–237. https://doi.org/10.1016/j.quascirev.2016.05.032

Tanno K., Willcox, G. 2006. How fast was wild wheat domesticated? Science 311:1,886

Weide, A., Green, L., Hodgson, J.G. et al. 2022. A new functional ecological model reveals the nature of early plant management in southwest Asia. Nature Plants 8:623–634.

Willcox G., Roitel V., 1998 Rapport archéobotanique préliminaire de trois sites préceramiques du Moyen Euphrate (Syria). Cahiers de l’Euphrate 8: 65-84.

Willcox, G. 2023. Can a functional ecological model reliably reveal the nature of early plant management in southwest Asia? Nature Plants: https//:doi: 10.1038/s41477-023-01573-z.

Willcox, G. 2024. Sowing, harvesting and tilling at the end of the Pleistocene/beginning of the Holocene in northern Syria: a reassessment of cereal and pulse exploitation. Vegetation History and Archaeobotany https://doi.org/10.1007/s00334-023-00984-4

Willcox, G., Fornite, S., Herveux, L. 2008. Early Holocene cultivation before domestication in northern Syria. Vegetation History and Archaeobotany 19(1): 151–8.

Willcox, G., Stordeur, D. 2012. Large-scale cereal processing before domestication during the tenth millennium cal BC in northern Syria. Antiquity 86:99–1141.

Zohary D, Hopf M. 2000. Domestication of plants in the Old World, 3rd edn. Oxford: Oxford University Press

L’auteur / The author

George Willcox is an associated researcher to the laboratory Archéorient (UMR 5133).

George Willcox est chercheur associé au laboratoire Archéorient (UMR 5133).


OpenEdition vous propose de citer ce billet de la manière suivante :
George Willcox (14 juin 2024). Early Neolithic cereal exploitation in Southwest Asia : gathering or cultivation? Bioarchéologies. Consulté le 15 juillet 2024 à l’adresse https://doi.org/10.58079/11txq


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