In order to improve FPS, a rapid, accurate and reliable method of estimating FPS is required for use during breeding and selection. FPS is calculated by dividing the mass of lint on one seed by the weight of one fibre. The weight of one fibre is determined by multiplying fibre length × length uniformity × fineness. Fineness is the weight per unit length of the fibre and can be directly measured on a select number of instruments such as the Shirley Fineness Maturity Tester (FMT) (ASTM, 1997), USTER® Advanced Fiber Information System (AFIS) (Montalvo and Hoven, 2005), or Cottonscope (Rodgers et al., 2012).