Cotton Lint Quality as Influenced by Harvest-Aid Regimes and Variety Characteristics.

Defoliation of cotton, Gossypium hisrutum L., has been refered to as  more art than a science by industry leaders.  The remnants of leaf material in harvested cotton can significantly reduce the grade of the lint and results in dockage to the producer.  Cotton classed through  of the USDA-AMS Classing office in Corpus Christi, Texas office has reported concerning increases in leaf grade beginning in 2000.  Major factors potentially influencing this increase include: excessive vegative growth, varietal impacts, harvest-aid regimes, and ginning techniques.  The impacts of the agronomic variables were studied during the 2010 growing season  in three counties in Texas.   Harvest-aid trials, repeated  in Brazos and Colorado counties, consisted of a range of chemical defoliants, desiccants, and boll-openers.  Chemical combinations were used in a variety of application sequences to create a range of defoliation levels and included numerous grower standards.  Impacts of varietal characteristics on leaf grade were studied in a variety trial, located in Wharton county, consisting of ten varieties and a single harvest aid technique.  The interaction between cotton variety leaf hairiness and harvest-aid regime study was conducted in Colorado county.  Stoneville 5458, a hairy leaf variety, and Dyna-Gro 2570, a smooth leaf variety, were treated with five diverse harvest-aid regimes to create varying levels of defoliation  All samples were transported and ginned at the Texas A&M University Agrilife Research Center in Lubbock, Texas to mimic a commercial ginning.