Figure 3. Average ambient photoperiod (includes civil twilight), experienced by 15 near-isogenic lines (NILs) grouped based on number of dominant E-gene alleles (E₁ counted as 2 dominant alleles), during their respective R1 to R5 stage of development under an early and late planting-date treatment. Data are averaged over 2003 and 2004. The bars represent standard error of the means.