Changes in Boll Development, Yield, and Fiber Quality of Commercial Cotton Varieties over Time Based on Date of Release

Fourteen cotton varieties representing various decades (1900’s to 2016) of release from the Stoneville and Deltapine lineage were planted in a randomized complete block design with four replications at the Pee Dee REC located in Florence, SC and at the Sandhills REC located in Jackson Springs, NC during the 2016, 2017, and 2018 growing seasons.  Plots consisted of four rows, 40 feet in length. Vegetative growth was monitored at various times during the season via leaf dry weights, stem dry weights, specific leaf weights, and leaf area indexes.  Reproductive growth was also monitored by both number and dry weights of squares, flowers, and bolls.  Plots were harvested with spindle type cotton pickers modified for small plot research. A seed cotton grab sample was collected from each plot, air dried, weighed and ginned. A subsample of lint was also collected for HVI fiber quality analysis.