A quick guide to PGR requirements for popular cotton varietiesA quick guide to PGR requirements for popular cotton varieties

Plant growth regulator applications are often necessary in cotton to reduce vegetative growth and maintain a manageable crop in Georgia.  Making PGR decisions can be difficult because of the many factors that need to be considered.

Cotton variety plays a role in making proper PGR decisions since some cotton varieties need to be monitored closely and heavily managed while some are sensitive, and overuse may negatively impact growth and development, and ultimately yield. 

Research conducted since 2010 has investigated the response of various varieties to two different PGR regimes: cotton which was not treated with PGR and cotton treated with mepiquat chloride three times (applied at initiation of squaring at 12 oz/A, at first bloom at 16 oz/A, and two weeks after first bloom at 16 oz/A). 

Growth parameters, particularly end-season plant height, along with lint yield and fiber quality were used to assess the growth potential of a variety and document the impact a heavy PGR regime has on development and yield.

Grouping of varieties into classes was developed to simplify PGR decisions based on variety and help growers make more education decisions when planting varieties for the first time.  When a new variety is planted, PGR decisions could be based on its PGR classification due to being in the same class as a more familiar variety or because it is in a different class than a familiar variety.  This system was also developed so that future investigations of PGR needs of new varieties can be more easily evaluated and quickly determined.