Genomic regions with significant trait associations in the Bay X Sha recombinant inbred population. Colored boxes indicate regions associated with UV-B-induced cotyledon opening (under cellulose di-acetate). White and hatched boxes indicate regions associated with cotyledon opening with no significant environmental effect in the comparison of UV-B treatments with control no-UV-B (Mylar) treatments. Colored boxes indicate UV-B-specific loci. Horizontal lines connect epistatic QTL. Significant loci are named by the population, chromosome, and map distance.