Plant breeders, biologists and bioinformatics specialists from ten countries, seven US states and two plant agribusinesses gathered in Corvallis, Oregon, September 13th-15th, 2012 for a Crop Plant Trait Ontology Workshop. The workshop was hosted by the Plant Ontology and the Trait Ontology, and co-organized by TransPlant, European Bioinformatics Institute, GARNet, Generation Challenge Program, Sol Genomics Network, and SoyBase.