The ‘King of Crops’: Rediscovering Ancient Diversity in Barley Through Chaff Morphology

Barley was central to the emergence of agriculture in western Asia and is today one of the world’s most widespread cereal crops. Rather than a single taxon, barley encompasses four major varieties (hulled two-row, hulled six-row, naked two-row, naked six-row) alongside its wild progenitor. We review the range of barley’s ecological and culinary properties to illustrate the importance of tracing its diversity and roles in the past, and its potential relevance in future farming and food cultures. A lack of comprehensive archaeobotanical identification criteria to distinguish all five barley taxa has limited understanding of the diversity and roles of barley from the Neolithic onwards in western Asia and beyond. Here, we show that the five forms of barley can be distinguished based on rachis morphology. Application of these identification criteria to western Asian Neolithic-Bronze Age archaeological assemblages demonstrates early diversity and change through time in favoured varieties of barley, with implications for its evolving roles.