The cotton plants are now placing all of their remaining energy into boll development and no more harvestable fruit is being set. Under optimum growing conditions, it would take about 50 days for the boll to open after pollination and one can describe boll development in three phases; namely enlargement, filling and maturation.
The enlargement phase of cotton boll development lasts about 3 weeks. It is during this time that the fibers produced on the seed are elongating and the maximum volume of the boll and seeds is attained. The fiber development is very sensitive to adverse environmental conditions, like moisture stress, which could reduce fiber strength, and this could be a factor in fiber quality with this years drought.
The fourth week after flowering is known as the filling phase at which time fiber elongation ends and the secondary wall formation of the cotton fiber begins. Cellulose is deposited inside the elongated fiber every 24 hours, filling the void space of the elongated fiber.
As the cotton boll reaches its full size and weight, it begins the maturation phase. During this time the seed and fiber mature, while the boll begins to split open, caused by capsule walls drying and cells shrinking unevenly. A rain now would sure be welcomed to help complete the boll maturation process.
