Fig. 4

Illustration and scatter plot of tassel length calculation. a Example of branch and spike identification for four different tassels. Cubic smoothing splines fit to branches shown in green, with the cubic smoothing spline along the main spike shown in red. Tassel length is calculated as the line integral of the red spline. b Plot of genotype means as obtained by manual and image-based measurement methods. Red line represents the fit of the manual onto the image-based measurements, and the gray shaded region represents the 95% confidence interval of the fit. The black dashed line represents a one-to-one relationship between manual and image-based measurements