Molecular Insights on the Domestication of Barley (Hordeum vulgare L.)

Abstract

Barley, Hordeum vulgare L., was first domesticated at about 8000 BCE. Throughout the domestication process, selection in the wild species resulted in the loss of seed shattering, minimization of seed dormancy, and an increase in both seed size and number. Three critical domestication traits were a non-brittle rachis, a six-rowed spike, and a naked caryopsis. After primary domestication, some adaptive traits subsequently developed, such as shortened seed dormancy and early flowering time, which are probably associated with genetic mutations affecting protein structure and function. Multiple genetic pathways formed a complex regulatory network due to interactions between the pathways. Recent studies on barley domestication genes have provided a framework for understanding how these traits evolved and have revealed that drastic changes in gene function occurred during domestication. In this paper, we review the current molecular insights into H. vulgare domestication and discuss the domestication genes that underlie morphological trait changes in the evolutionary history of barley.