Figure 1: External validation using environmental blocking for days-to-bolting. For all plantings except RS, models were trained on data from six plantings (excluding RS) and validation performed on the seventh planting. For RS, the model was trained on 100% of the data from seven plantings and compared against the median DTB as reported by Korves and colleagues (2007). HF = Halle, Fall 2006. NF = Norwich, Fall 2006. NSP = Norwich, Spring 2007. NSU06 = Norwich, Summer 2006. NSU07 = Norwich, Summer 2007. OF = Oulu, Fall 2007. VF = Valencia, Fall 2006.