Diversity of Free-Threshing Wheat in Early Medieval England Supported by Geometric Morphometric Analysis of Grains

Observations of atypical grains and relatively small quantities of diagnostic rachis fragments have led to suggestions that a new type of wheat was introduced into Late Anglo-Saxon agriculture (c. AD 850–1066). This crop was a tetraploid free-threshing wheat (FTW), potentially unknown in Britain since the Neolithic. Based on growing requirements, this wheat is considered to have most likely been rivet, a tall cultivar associated with thatching, presumably grown alongside hexaploid bread wheat. However, cultivation of this crop has not been conclusively demonstrated because traditional morphological approaches do not allow us to identify specific FTW cultivars. New results suggest geometric morphometric analysis can distinguish FTW grains at different taxonomic levels. Modern wheat specimens were compared with >450 charred grains from contexts spanning the 7th–14th centuries at twelve sites, accessed through the ‘Feeding Anglo-Saxon England’ (FeedSax) project. The presence of rivet wheat is suggested at several sites, before and after the Norman Conquest (AD 1066), with intra-species comparisons indicating greater similarity to ‘traditional’ varieties than to modern ‘improved’ forms. Morphological variation relating to diversity both within and between cultivars is described and interpreted within the context of innovations in arable production in the later Anglo-Saxon period.