Contrasting Patterns in Crop Domestication and Domestication Rates: Recent Archaeobotanical Insights from the Old World

Institute of Archaeology, University College London, 31-34 Gordon Square, London WC1H 0PY, UK.
Annals of Botany (Impact Factor: 3.65). 12/2007; 100(5):903-24. DOI: 10.1093/aob/mcm048
Source: PubMed


Archaeobotany, the study of plant remains from sites of ancient human activity, provides data for studying the initial evolution of domesticated plants. An important background to this is defining the domestication syndrome, those traits by which domesticated plants differ from wild relatives. These traits include features that have been selected under the conditions of cultivation. From archaeological remains the easiest traits to study are seed size and in cereal crops the loss of natural seed dispersal.
The rate at which these features evolved and the ordering in which they evolved can now be documented for a few crops of Asia and Africa. This paper explores this in einkorn wheat (Triticum monococcum) and barley (Hordeum vulgare) from the Near East, rice (Oryza sativa) from China, mung (Vigna radiata) and urd (Vigna mungo) beans from India, and pearl millet (Pennisetum glaucum) from west Africa. Brief reference is made to similar data on lentils (Lens culinaris), peas (Pisum sativum), soybean (Glycine max) and adzuki bean (Vigna angularis). Available quantitative data from archaeological finds are compiled to explore changes with domestication. The disjunction in cereals between seed size increase and dispersal is explored, and rates at which these features evolved are estimated from archaeobotanical data. Contrasts between crops, especially between cereals and pulses, are examined.
These data suggest that in domesticated grasses, changes in grain size and shape evolved prior to non-shattering ears or panicles. Initial grain size increases may have evolved during the first centuries of cultivation, within perhaps 500-1000 years. Non-shattering infructescences were much slower, becoming fixed about 1000-2000 years later. This suggests a need to reconsider the role of sickle harvesting in domestication. Pulses, by contrast, do not show evidence for seed size increase in relation to the earliest cultivation, and seed size increase may be delayed by 2000-4000 years. This implies that conditions that were sufficient to select for larger seed size in Poaceae were not sufficient in Fabaceae. It is proposed that animal-drawn ploughs (or ards) provided the selection pressure for larger seeds in legumes. This implies different thresholds of selective pressure, for example in relation to differing seed ontogenetics and underlying genetic architecture in these families. Pearl millet (Pennisetum glaucum) may show some similarities to the pulses in terms of a lag-time before truly larger-grained forms evolved.

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Available from: Dorian Q Fuller, Sep 30, 2015
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    • "On the other hand, herbivores feeding on larger fruit can be more likely to escape parasitism, such as the apple maggot fly, Rhagoletis pomonella (Walsh), which are parasitized less on the larger apple fruit than on fruit of their native hawthorn trees (Feder, 1995). Grain and legume plants have been repeatedly selected for larger seeds (Evans, 1993; Fuller, 2007; Schmutz et al., 2014). It has been proposed that seed size evolved as a trade-off between the probability of survival after germination and the number of seeds. "
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    ABSTRACT: Crop domestication is the process of artificially selecting plants to increase their suitability to human tastes and cultivated growing conditions. There is increasing evidence that crop domestication can profoundly alter interactions among plants, herbivores, and their natural enemies. However, there are few generalizable predictions on how insect herbivores and natural enemies should respond to artificial selection of specific plant traits. We reviewed the literature to determine how different insect herbivore feeding guilds and natural enemy groups (parasitoids and predators) respond to existing variation in wild and cultivated plant populations for plant traits typically targeted by domestication. Our goal was to look for broad patterns in tritrophic interactions to generate support for a range of potential outcomes from human-mediated selection. Overall, we found that herbivores benefit from directional selection on traits that have been targeted by domestication, but the effects on natural enemies were less studied and less consistent. In general, herbivores appear to mirror human preferences for higher nutritional content and larger plant structures. In contrast, the general effect of lowered plant secondary metabolites did not always influence herbivores consistently. Given that crop domestication appears to be a transformative process that fundamentally alters insect–plant interactions , we believe that a more detailed understanding of the community-wide effects of crop domesti-cation is needed to simultaneously stimulate both biological control and plant breeding efforts to enhance sustainable pest control.
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    • "Archaeobotanical research resulted in the abandonment of the hypothesis of a single core area for the origins of agriculture within the Fertile Crescent [11] [12]. The accumulated record of archaeobotanical assemblages with different proportions of wild and domesticated species supported the model of protracted domestication lasting up to 2000 years ([2] [11] [13] [14], but see also [15] for a different opinion). The term " protracted domestication " is often used with absolute chronological designations, for example, marking the time range between BioMed Research International large-scale systematic gathering of wild cereals at Ohalo II around 23.000 BP and the appearance of the first domesticated species during the PPNB [13], contrasted with possible " rapid domestication " resulting from the intentional selection of domesticated phenotypes which may take place within a few cereal generations [16]. "
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    ABSTRACT: The evidence for the slow development from gathering and cultivation of wild species to the use of domesticates in the Near East, deriving from a number of Epipalaeolithic and aceramic Neolithic sites with short occupational stratigraphies, cannot explain the reasons for the protracted development of agriculture in the Fertile Crescent. The botanical and faunal remains from the long stratigraphic sequence of Chogha Golan, indicate local changes in environmental conditions and subsistence practices that characterize a site-specific pathway into emerging agriculture. Our multidisciplinary approach demonstrates a long-term subsistence strategy of several hundred years on wild cereals and pulses as well as on hunting a variety of faunal species that were based on relatively favorable and stable environmental conditions. Fluctuations in the availability of resources after around 10.200 cal BP may have been caused by small-scale climatic fluctuations. The temporary depletion of resources was managed through a shift to other species which required minor technological changes to make these resources accessible and by intensification of barley cultivation which approached its domestication. After roughly 200 years, emmer domestication is apparent, accompanied by higher contribution of cattle in the diet, suggesting long-term intensification of resource management.
    BioMed Research International 09/2015; 2015(6):1-22. DOI:10.1155/2015/532481 · 3.17 Impact Factor
    • "Depending on the method and taxon, domestication can be recognised in the archaeobotanical record by anatomical differences between domesticates and their wild relatives (e.g. Beug, 2004, p. 74ff; Fuller, 2007; Piperno, 2006, p. 45ff.). However, it is more difficult to detect methods of plant management that did not result in the development of adaptive traits. "
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    21st annual meeting of the European Association of Archaeologists; 09/2015
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