Use of Growth Regulators in Cotton Production

Cotton (Gossypium hirsutum L.), a perennial woody shrub with an indeterminate growth habit, evolved in tropical, relatively dry areas of the world. Through adaptive changes, accomplished through breeding and selection, cotton is now widely grown under both semi-arid and humid conditions. However, despite these adaptive changes, cotton continues to exhibit many attributes of its tropical origin. The crop grows best under warm temperatures and high light intensity, is somewhat drought tolerant, and often continues or resumes growth late in the season. Because of these growth habits, alterations in growth and development of the crop are often agronomically desirable. These alterations may be accomplished through the use of plant growth regulators (PGRs). PGRs are classified as organic compounds that alter the growth and development of plants. PGRs are biologically active at very low concentrations, and elicit responses similar to those observed from plant hormones. Unlike plant hormones which are produced by the plant, PGRs may be either produced naturally by the plant or synthetically by a chemist. However, responses to PGRs are complicated by the interaction of environment and cultural practices. For a PGR to be widely accepted, it must perform consistently in a given production scheme.