For FD calculations (FPS divided by SSA), FDmic indicates where FPS determined via equation 1 was used to calculate FD, while FDfin indicates where equation 2 was used. Seed surface area (SSA) was calculated by the equation (35.74 + 6.59 × fuzzy seed index) (Groves and Bourland, 2010). FDmic and FDfin were plotted by regression analysis for individual experiments and collectively as a multiple linear regression taking fibre fineness and maturity ratio into account and demonstrating the variability of maturity ratio.