Postdomestication selection of MKK3 shaped seed dormancy and end-use traits in barley

Anthropogenic selection of grain traits such as dormancy has shaped the developmental trajectories of crops. In cereals, shortening dormancy provides rapid and even post-harvest germination, but increases the risk of weather-induced pre-harvest sprouting (PHS) with yearly harvest losses beyond 1 billion USD. Our understanding of how, why, when and where cereal dormancy diversification arose is fragmentary. Here, we show in the founder crop barley ( Hordeum vulgare ) that dormancy is primarily regulated through a mosaic of locus haplotypes comprising copy-number variation and inherent kinase activity of Mitogen-activated protein kinase kinase 3 ( MKK3 ). We provide evidence supporting the historical selection of specific MKK3 haplotypes that shape dormancy levels according to changing climatic pressures and outline a genetic framework for breeders to balance grain dormancy and PHS-avoidance.