Response of Cotton to Leaf and Terminal Removals at Various Growth Stages

A replicated field trial was conducted at the Pee Dee Research & Education Center located in Florence, SC in 2013 and 2014. Treatments consisted of 17 different combinations of leaf and terminal removal based on cotton growth stages.  Plants were either completely defoliated (100% defoliated) or had half there leaves removed (50% defoliated) by hand at the 4-leaf stage, at matchhead square, at early bloom, and at early bloom plus 2 weeks.  Terminals were also removed by hand in combination with the defoliation treatments on half the plots during the same growth stages.  An untreated check was also included.  Plots consisted of 4 rows, spaced 38 inches apart and were 40 feet long.  Data collected included boll size and numbers, and a final plant map at the end of the season (plant height, number of nodes, total fruiting sites, vegetative branches, boll location on main stem nodes and sympodia). At season’s end, plots were machine-harvested with a Case 1822 2-row picker.  Seedcotton was ginned on a 10-saw gin and gin turnout calculated, and fiber quality determined by HVI analysis at LSU fiber Lab.   Data were evaluated by analysis of variance (SAS Institute Inc., Cary, NC).