The domestication of cereals has involved common changes in morphological features, such as seed size, seed retention and modification of vegetative and inflorescence architecture that ultimately contributed to an increase in harvested yield. In barley, this process has resulted in two different cultivated types, two-rowed and six-rowed forms, both derived from the wild two-rowed ancestor, with archaeo-botanical evidence indicating the origin of six-rowed barley early in the domestication of the species, some 8,600-8,000 years ago. Variation at SIX-ROWED SPIKE 1 (VRS1) is sufficient to control this phenotype. However, phenotypes imposed by VRS1 alleles are modified by alleles at the INTERMEDIUM-C (INT-C) locus. Here we show that INT-C is an ortholog of the maize domestication gene TEOSINTE BRANCHED 1 (TB1) and identify 17 coding mutations in barley TB1 correlated with lateral spikelet fertility phenotypes.
Bibliographical noteFunding Information:
This research was supported by UK Sustainable Arable LINK 302 / BB/D522003/1 ‘Association Genetics of Elite UK Barleys’ and United States Department of Agriculture-Cooperative State Research, Education and Extension Service-National Research Institute (USDA-CSREES-NRI) grant no. 2006-55606-16722 ‘Barley Coordinated Agricultural Project; leveraging Genomics, Genetics, and Breeding for Gene Discovery and Barley Improvement’. We thank A. Roberts and S. Chapman (Scottish Crop Research Institute) for technical advice and M. Boulton and T. Moore (John Innes Centre) for guidance on sequencing SLENDER1.