Plant growth regulators (PGR's) are emerging as one of the most promising tools available to farm managers seeking ways to maximize productivity and profitability. Cotton as a crop is particularly well-suited to benefit from advances in PGR technology. Although we grow cotton as an annual, it evolved as a perennial woody shrub in tropical, dry areas of the world. The plant grows best in warm temperatures and high light intensity. It has adapted to periodic droughts by temporarily ceasing vegetative growth and shedding fruiting forms. When the water supply is replenished, a flush of new vegetation and fruiting forms insures reproductive survival. Energy reserves as starch are stored in its roots and stems to provide for continued survival into the next favorable growth cycle.

These botanic characteristics make cotton a challenging crop to manage successfully. The crop fruits over a long period of time requiring continued vigilance over insect pests. Drought stress may trigger undesirable fruit or square abortion. Excessive moisture coupled with available nitrogen, particularly following fruit abortion may trigger luxuriant or rank growth. Crop maturation is frequently followed by second growth signaling the onset of a new growth cycle. Plant growth regulators may be capable of favorably altering these inherent characteristics to produce a cotton plant with less foliage, more bolls and higher quality lint produced over a shorter period of time.

Plant growth regulators have been defined as chemicals that control plant growth. Using this definition water, oxygen, carbon dioxide, and nutrients may be considered PGR'S. In the arid and semi-arid areas of the cotton belt, the stature of the cotton plant may be regulated by the amount and timing of irrigations. Although we do not have much control over the levels of carbon dioxide or oxygen in the immediate environment of the cotton plant, the actual and relative levels of these two gases strongly influence the process of photosynthesis and the productivity of the cotton plant. Similarly, nutrient levels, particularly when deficient, will influence earliness, stature, and ultimate yield of cotton. Cotton workers across the belt continue to improve their management of these factors that fundamentally influence crop productivity.