Relationships of Plant Trichomes to Yield and Fiber Quality Parameters in Upland Cotton

Botanically, the hair on leaves, stems and bracts, as well as the fibers on seed are plant trichomes. Reducing trichomes on cotton leaves, stems and bracts can reduce trash in ginned cotton lint, but might negatively impact fibers on seed and other parameters. Our objective was to determine the impact of reducing trichomes on leaves, stems and bracts on number and density of fibers on seed and on other agronomic and fiber quality parameters. Trichome (leaf, stem and bract), agronomic (9 parameters) and fiber quality (6 parameters) data were extracted from the Keiser location of the Advanced and New Strain Tests (2006-2015) and the Main and 1st year Variety Test (2007-2015) in Arkansas. All agronomic and fiber quality data were analyzed using PROC GLM and a linear mixed model (PROC MIXED in SAS) with leaf pubescence, stem pubescence and bract trichomes as independent variables. Trends for trichome measures in Strain Tests differed from trends in Variety Tests. Leaf and stem pubescence influenced more parameters than bract trichome density. Increased leaf pubescence was related to higher yields in each test and with higher fibers seed-1 and fiber density in the Strain (but not the Variety) Tests. Bract trichome density did not affect any parameter (except fiber strength) in the University of Arkansas (UA) Cotton Breeding Program. Compared to leaf and stem pubescence, bract trichome density appears to have fewer adverse relationships with yield and quality parameters. Reducing bract trichome density should be the optimum method to lower plant hairiness in Upland cotton.