Text S1. Details of model-independent measures of within-line and between-line variance and linear mixed modeling. Model-independent measures of within-line and between-line variance Within-line and between-line variances for the HTZ1+ and HTZ1– genotypes were analyzed using using model-independent approaches

The median absolute deviation (MAD) of each trait (principal component) was used to measure within-line variance, as it is less sensitive to non-normality than other measures of spread [67, 68]. However, plotting the raw MADs of each line against the line median tended to show a dependency of the MAD on the median (Figure S2). To correct for this dependency, the residuals of a local (lowess) regression of MAD on median were used in place of raw MADs to compare differences in within-line variation, similar to our previous analysis [41].