Cotton fibre maturity has several definitions. Synonymous with ripeness, maturity may be that property which increases with the reproductive power of the seed, signalling to the plant that the seed containing part is ready to fall off and be blown away to germinate later. A generally accepted definition is that maturity refers to the level of secondary wall thickening that occurs during the latter half of fibre development. The extent of this thickening influences both chemical and physical characteristics of the fibre. The physical scientist, measures maturity as a function of the fibre wall thickness, expressed in some way, such as degree of thickening, that separates the genetic effect of fibre coarseness.