Evaluation of Plant Growth Regulators in Cotton

Evaluation of Plant Growth Regulators

Plant growth regulators have been labeled for use in cotton for decades.  Despite their age PGR’s continue to have a relatively low acceptance rate among cotton growers when compared to other chemicals such as pesticides.  However, research shows when used appropriately, PGR’s consistently prove their value as a management tool in cotton.  Benefits of PGR use in cotton include:  reduced rank vegetative growth, compact and uniform growth, and uniform maturity, all of which allow for an easier harvest.  This two location study evaluates the performance of STANCE^® and mepiquat chloride over five cotton varieties at two population densities.  PGR treatments were applied starting at match head square (MHS), additional treatments were applied at MHS plus fourteen days, and MHS plus twenty-eight days.  STANCE^® was applied three times at two rates, 2 oz per acre and 3 oz per acre.  Mepiquat chloride was applied at 4, 8, and 12 oz per acre respectively.  Fibermax 1880, 9180, 1740 and Stoneville 4498, 5458 were planted at three and five seed per foot densities.  Both locations are well watered.  Nodes above white flower and nodes above cracked boll measurements were taken throughout the experiment to monitor maturity.  Plant height data was also collected throughout the study.   Yield data will be determined by a mechanical harvester.  The Fiber and Biopolymer Research Institute in Lubbock, Texas  assesed the fiber quality by using AFIS and HVI. The different chemical treatments have no affect on the total nodes; however NAWF was influenced. Height differences are observed among the three treatments. However the main height differences seen can be attributed to the different cotton varieties. The seeding rate affected the height, nodes and NAWF.  The chemical treatments did affect some quality parameters.