The nine PRO2+ and INT6+ haplotypes tested in transgenic experiments were present in 579 (69%) of all 840 accession with available genome sequence information (Figure 8—figure supplement 1A). To examine whether these haplotypes explain natural variation of FLM-ß levels in natural accessions, we randomly selected an experimental population of 94 accessions (2 to 14 accessions per PRO2+/INT6+ group, average 10) with a broad genetic and geographic distribution (Figure 8—figure supplement 1B,C). We next determined FLM-ß expression and, following quality filtering, grouped 85 accessions according to their PRO2+ or INT6+ haplotypes (Supplementary file 6A).