For many crops, wild relatives constitute an extraordinary resource for cultivar improvement [1, 2] and also help to better understand the history of their domestication [3]. However, the wild ancestor species of several perennial crops have not yet been identified. Perennial crops generally present a weak domestication syndrome allowing cultivated individuals to establish feral populations difficult to distinguish from truly wild populations, and there is frequently ongoing gene flow between wild relatives and the crop that might erode most genetic differences [4]. Here we report the discovery of populations of the wild ancestor species of the date palm (Phoenix dactylifera L.), one of the oldest and most important cultivated fruit plants in hot and arid regions of the Old World. We discovered these wild individuals in remote and isolated mountainous locations of Oman. They are genetically more diverse than and distinct from a representative sample of Middle Eastern cultivated date palms and exhibit rounded seed shapes resembling those of a close sister species and archeological samples, but not modern cultivars. Whole-genome sequencing of several wild and cultivated individuals revealed a complex domestication history involving the contribution of at least two wild sources to African cultivated date palms. The discovery of wild date palms offers a unique chance to further elucidate the history of this iconic crop that has constituted the cornerstone of traditional oasis polyculture systems for several thousand years [5].

Aim  The main purpose of this work is to understand the origin, history, historical biogeography and mechanisms of date palm (Phoenix dactylifera L.) domestication.Location  Seeds of uncultivated Phoenix individuals from isolated Oman populations, cultivated date palm varieties of various geographical origins and other related Phoenix species were analysed. Additionally, well‐preserved seeds from Egyptian archaeological sites (14th century bc to 8th century ad) were compared with the morphometric reference model based on the analysis of modern material.Methods  Elliptic Fourier transforms (EFT), a morphometric method applied to shape outline analysis, were used to characterize seed shape and to quantify morphological diversity in P. dactylifera and related species.Results  Analysis of seed outlines by EFT (1) showed that P. dactylifera can be differentiated from other Phoenix species and (2) enabled the quantification of patterns of shape differentiation in the genus Phoenix at different taxonomic, geographical and chronological levels. Date palm agrobiodiversity, partitioned in distinct morphotypes, appeared to be complex in terms of geographical structure. Allocation of archaeological seeds to different modern Phoenix forms and date palm morphotypes allowed us to reveal ancient forms consumed and/or exploited in Egypt and finally to determine spatial and temporal changes in agrobiodiversity.Main conclusions  Based on the morphological diversity quantified in P. dactylifera and related species, we characterized ancestral seed shape features present in uncultivated populations. The geographical distribution pattern of seed shapes points to human dispersal routes that spread cultivation from one or more initial ‘domestication centres’. Finally, this work provides a powerful tool to identify ancient forms as demonstrated by the analysis of well‐preserved Egyptian archaeological seeds, dating from the 14th century bc to the 8th century ad. Results open new and fascinating perspectives on the investigation of the origins and chrono‐geographical fluctuation of date palm agrobiodiversity.

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Investigating crop origins is a priority to understand the evolution of plants under domestication, develop strategies for conservation and valorization of agrobiodiversity and acquire fundamental knowledge for cultivar improvement. The date palm (Phoenix dactylifera L.) belongs to the genus Phoenix, which comprises 14 species morphologically very close, sometimes hardly distinguishable. It has been cultivated for millennia in the Middle East and in North Africa and constitutes the keystone of oasis agriculture. Yet, its origins remain poorly understood as no wild populations are identified. Uncultivated populations have been described but they might represent feral, i.e. formerly cultivated, abandoned forms rather than truly wild populations. In this context, this study based on morphometrics applied to 1625 Phoenix seeds aims to (1) differentiate Phoenix species and (2) depict the domestication syndrome observed in cultivated date palm seeds using other Phoenix species as a “wild” reference. This will help discriminate truly wild from feral forms, thus providing new insights into the evolutionary history of this species. Seed size was evaluated using four parameters: length, width, thickness and dorsal view surface. Seed shape was quantified using outline analyses based on the Elliptic Fourier Transform method. The size and shape of seeds allowed an accurate differentiation of Phoenix species. The cultivated date palm shows distinctive size and shape features, compared to other Phoenix species: seeds are longer and elongated. This morphological shift may be interpreted as a domestication syndrome, resulting from the long-term history of cultivation, selection and human-mediated dispersion. Based on seed attributes, some uncultivated date palms from Oman may be identified as wild. This opens new prospects regarding the possible existence and characterization of relict wild populations and consequently for the understanding of the date palm origins. Finally, we here describe a pipeline for the identification of the domestication syndrome in seeds that could be used in other crops.

Recent archaeological research at Saruq al-Hadid, Dubai, UAE In September 2014, the University of New England (UNE), Australia, began a threeyear programme of archaeological fieldwork and post-excavation analyses focused on the site of Saruq al-Hadid. In this paper, we present the initial results of our current field and laboratory research particularly related to site stratigraphy and formation processes, relative and absolute chronology, and the preliminary results of various programmes of post-excavation analyses including archaeobotanical, zooarchaeological, ceramic and archaeometallurgical studies. These studies provide new data to build into the archaeological understanding of Saruq al-Hadid that has, to date, focused largely on intensive excavation.

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