General Procedures

Official Variety Trials

Seven OVTs were planted in the 2018 growing season.  These included four locations on University of Tennessee Research and Education Centers and two locations on producer farms.  Seed of commercial cultivars and experimental lines was provided by respective companies. In all, 60 varieties were evaluated.  Each variety was randomly assigned to four plots at each location and each plot was arranged in a randomized complete block design. Individual plots consisted of two 30 ft rows.  Soil samples were collected prior to planting and fertilizer and lime were applied according to test results and UT recommendations. At planting, a systemic insecticide and fungicide were applied in-furrow.

Between 120 and 130 days after planting (DAP), plant height, node of first fruiting branch, total nodes, and a rating of percent open was collected in each plot. Weed and pest control measures were uniformly applied to all plots per UT-recommendations. Seed cotton was harvested from each plot by either a two row picker outfitted with an in-basket, catch-and-weigh system or a catch-system.  Each plot was subsequently harvested, weighed, and subsampled for turnout and fiber quality.  Subsamples from each location were then air-dried, bulked by varietal entry and weighed prior to ginning.

Large Plot Variety Trials

Thirteen CSTs were conducted in the 2018 growing season.  These included one location on the West Tennessee Research and Education Center, one location on the Ames Plantation Research and Education Center, and 11 locations on production fields.  Seed of commercial varieties was provided by each respective company.  In all, 18 varieties were submitted. Each variety was planted in a single plot at each location and was maintained per the individual producer’s production practices. Plot size ranged from two to eight rows wide and 125 to 2500 ft+ in length, depending on producer equipment and field size.

At harvest, plots were picked with the producer’s equipment.  If using a basket-style picker, weights were collected by catching harvested plots from the picker with a weighing boll buggy prior to dumping into the module builder. If using an on-board round module picker, modules were wrapped at the end of each plot and weighed on a set of transportable scales.  Regardless of picker type, an 8-12 lb sub-sample was collected after the picked plot weight was determined.  These samples were then air dried and weighed prior to ginning.


Samples were ginned at the University of Tennessee Cotton MicroGin located at the West Tennessee Research and Education Center in Jackson, TN. This is a 20-saw gin equipped with a stick machine, incline cleaners, and two lint cleaners.  No heat was applied at ginning.  Lint yields on a per-plot basis were then calculated from gin turnouts and harvested plot areas.  A subsample of lint from each ginned sample was submitted to the USDA Cotton Classing Office in Memphis, TN for HVI analysis.

Statistical analysis

For OVT locations, mean separation of fiber quality was calculated for the combined dataset including all analyzed locations by considering location as replication.  Mean separation of OVT variety yield by location was calculated by a PROC MIXED model (SAS Institute, Inc., Cary, NC) considering replication to be random.  Combined analysis was also calculated by a PROC GLM model, with location and replication nested in location considered to be random.  Mean separation of fiber quality and lint yield for the CST combined dataset was calculated by considering location as replication.  This analysis was calculated by a PROC GLM model considering replication as a random factor and variety as a fixed factor.  Similarly, the replicated CI trials were analyzed considering location and replication nested in location to be random.

Seed Sources

Companies which participated in the 2018 University of Tennessee Cotton Variety Testing Program and their subsequent entries are listed below:

  • American Cotton Breeders, Inc. 5210 88th Street, Lubbock, TX 79424

NG 3517 B2XF               NG 3522 B2XF               NG 3699 B2XF               NG 3729 B2XF                                       NG 3780 B2XF               NG 4601 B2XF                  NG 4689 B2XF               NG 4777 B2XF                                       NG 5007 B2XF               AMX 1801 B3XF            AMX 1815 B3XF            AMX 1816 B3XF

AMX 1817 B3XF            AMX 1818 B3XF            AMX 1819 B3XF

  • Bayer CropScience, 311 Poplar View Lane West, Collierville, TN 38017

ST 4949 GLT                  ST 5020 GLT                  ST 5122 GLT                  ST 5471 GLTP

ST 5517 GLTP                ST 5818 GLT                  BX 1973 GLTP               BX 1974 GLTP

BX 1975 GLTP               BX 1976 GLTP

  • Croplan Genetics, 8700 Trail Lake Dr., Suite 100, Memphis, TN 38125

CP 3475 B2XF                CP 9608 B3XF                CP 9178 B3XF                CP 18XC9 B3XF

  • Crop Production Services, 3005 Rocky Mountain Ave., Loveland, CO 80538

DG 3214 B2XF               DG 3385 B2XF               CPS 18864 GLTP            CPS 18507-B B3XF

CPS 18817 B3XF

  • Monsanto, P.O. Box 157, Scott, MS 38772

DP 1518 B2XF               DP 1614 B2XF               DP 1646 B2XF               DP 1725 B2XF

DP 1820 B3XF               DP 1835 B3XF               MON 17R818B3XF         MON 17R821B3XF

  • Phytogen Seed Co., P.O. Box 27, Leland, MS 38756

PHY 300 W3FE              PHY 320 W3FE              PHY 330 W3FE              PHY 340 W3FE

PHY 350 W3FE              PHY 430 W3FE              PHY 440 W3FE              PHY 480 W3FE

PX5C09W3FE                PX3B07W3FE                PX3B09W3FE                PX3C06W3FE

PX4A64W3FE                PX4A69W3FE                PX5D28BW3FE              PX5B73W3FE

  • Seed Source Genetics, 5159 FM 3354, Bishop, TX 78343

SSG UA 222                   SSG UA 114

Tyson Raper

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