Searching for the Origins of Bere Barley: a Geometric Morphometric Approach to Cereal Landrace Recognition in Archaeology

M Wallace,L Ramsay,S Timpany,T S George,J Russell,H Bull,E Stillman,J Wishart,A Booth,V Bonhomme,P Martin

doi:10.1007/s10816-018-9402-2

Abstract

Bere is a landrace of barley, adapted to the marginal conditions of northern Scotland, especially those of the Northern and Western Isles. The history of bere on these islands is long and, in an era of diminishing landrace cultivation, bere now represents one of the oldest cereal landraces in Europe still grown commercially. The longevity of bere raises the possibility of using grain characteristics of present-day specimens to identify bere in the archaeological record. Geometric modern morphometric (GMM) analysis of grains from bere and other barley landraces is conducted to determine whether landraces can be differentiated on grain morphology. Results indicate that there are morphological differences between bere and other British and Scandinavian landraces, and between bere from Orkney and the Western Isles, both of which are apparent in genetic analysis. This finding paves the way for the identification of bere archaeologically, helping to establish its status as living heritage and securing its commercial future. More broadly, this work indicates the potential of grain GMM for the recognition of cereal landraces, permitting the ancestry and exchange of landraces to be traced in the archaeological record.

Highlights

The spread of agriculture beyond the regions of cereal domestication in the Fertile Crescent of southwest Asia was a lengthy process crossing biogeographic boundaries
Fifty-four accessions which represent both two- and six-row barleys grown across the UK and Scandinavia during the last hundred years, along with bere barleys from Orkney and the Western Isles were genotyped with 3072 mapped genetic markers (BOPA1&2, Close et al 2009)
The Geometric modern morphometric (GMM) data were noisier than the single nucleotide polymorphism (SNP) data, though linear discriminant analysis (LDA) shows these accessions separate into groups with similar membership to those based on SNP data (Fig. 2)

Summary

Introduction

The spread of agriculture beyond the regions of cereal domestication in the Fertile Crescent of southwest Asia was a lengthy process crossing biogeographic boundaries. The continued viability of agriculture as it spread across Europe, especially along the latter northwards trajectory, required crops to adapt to environmental conditions starkly different to those under which they were first domesticated (Bogucki 2000; Bonsall et al 2002; Halstead 1989). This is exemplified by adaptations in responsiveness to daylength with the northwards spread of agriculture (Jones et al 2012) and observed adaptation to specific abiotic stresses (George et al 2014; Schmidt et al in prep.). The presence of two-row (H. vulgare var. distichum) and six-row (H. vulgare var. hexasticum) forms can be inferred, at the assemblage level, by the ratio of straight (central) and twisted (lateral) grains, and naked forms (H. vulgare var. nudum) by the absence of hulls on grains, but further identification to the level of landrace is not attempted

Methods

Results

Discussion

Conclusion