Development of an Industry-Wide Standard for Leaf Hairiness

Cotton leaf grade is a visual estimation of the amount of plant material in a lint sample on a scale of 1 to 7, with 1 being the ideal score (Larson and English, 2001).  Plant material in harvest lint is waste, and can result in price dockage for the producer because additional processing is required to remove the plant material.  Previously, several factors were believed to negatively influence the leaf grade values, including the level of leaf defoliation and desiccation prior to harvest.  However, recent research by Eder, et al., 2013 and Boykin et al., 2013 identified leaf hairiness as being a primary culprit in higher leaf grade values. Additionally, during these trials, discrepancies in seed company ratings for leaf hairiness and quantified trichome densities were observed. Due to these findings, there is widespread support from agronomists, plant breeders, and ginners to obtain an objective and robust method for quantifying an industry-wide standard for leaf hairiness.  From existing small plot variety trials in 2013-2015 in Palacios, TX, Lubbock, TX, Keiser, AR, and Tifton, GA, leaf trichome densities were quantified across major cotton production regions.  A common variety with high trichome densities were included at each location.  Trichome densities were quantified using the methods described by Bourland et al. 2003. A three summary of the results will be presented, and the proposed methodology for an industry-wide the leaf hairiness index will be presented.