Performance of Various Cotton Varieties in Replicated Large-Plot and Small-Plot Research Trials in South Carolina

Variety selection is the first and perhaps the most important management decision a grower makes each season.  In recent years, growers have expressed to industry leaders a desire to have more information to help them make better seed purchase decisions  Questions exist among cotton  researchers and their clientele on which method of variety testing is best for the southeastern coastal plain.  Therefore, large-plot and small-plot replicated cultivar trials were conducted in five separate locations throughout South Carolina to compare variety testing methods and to determine the best method to evaluate cotton varieties in South Carolina. 

Small- and large-plot replicated variety trials were established at four separate locations during the 2013 growing season.  Trial locations were selected based on historical  and projected cotton acreage in a given area and differences in soil types and management inputs.   Trial locations planted were Dillon (Minturn, SC), Florence (PDREC), Lee (Elliott, SC), and Calhoun (St. Matthews, SC) counties.  Large-plot trials consisted of 10 popular commercial varieties planted  in a randomized complete block design with 4 replications.  Large-trial plot size consisted of  2 to 4 rows (38 or 40 inch rows) per variety x 350 to 500 feet long.  Small-plot trials consisted of  50 to 54 varieties that were split into early and late-maturity trials (24 to 28 varieties/trial).  Experimental design was a randomized complete  block with 4 replications.  Plot size consisted of  2 rows (38 or 40 inch)  x 40 feet long.  Large- and small-plot replicated trials were planted on the same day  with the same planter in adjoining areas in the same field.  Both small- and large-plot trials  were managed by cooperators with the same production practices and inputs.