The term fiber maturity is generally understood to refer to the degree of development or

thickening of the fiber secondary wall [566,567]. Fiber maturity is a function of the growing

conditions that can control the rate of wall development and of catastrophic occurrences such

as premature termination of growth due to such factors as insect infestation, disease, or frost.

As we have seen, the fiber develops as a cylindrical cell with a thickened wall. As the diameter

of the fiber cylinder is largely genetic or species-dependent, a simple absolute measure of the

thickness of the fiber secondary wall is not sufficient to define maturity. Probably the best

definition of cotton fiber maturity has been proposed by Raes and Verschraege [568] who

state ‘‘. . . the maturity of cotton fibers consists in defining it as the average relative wall

thickness.’’ What is implied in this statement is that maturity is the thickness of the cell wall

relative to the diameter or perimeter of the fiber.