Comparison of Large-Plot and Small-Plot Replicated Variety Trials in the Southeastern Coastal Plain

Cultivar selection is the first and perhaps the most important management decision a grower makes each season.  Cultivar decisions are now more complex due to the fact that numerous new cultivars have been introduced to the market by seed companies during the last few years.  Many new cultivars are now offered for sale with fewer years of public testing than most growers, consultants, and university personnel need for proper evaluation.  One way to increase the number of environments or evaluations of a new cultivar is to increase the number of locations within a given year.  Increasing the number of locations within a given year will expose a new cotton cultivar to as many different growing conditions, management inputs, soil types, and environmental stresses as possible, and hopefully expose any problems associated with the performance of a cultivar before it reaches growers’ fields.   Proper field testing of varieties will become even more important during the next few years with the development and release of new Roundup Ready Flex, Widestrike, Liberty-Link, and Bollgard II varieties.  Growers will soon become overwhelmed by the influx of potential new varieties offered for sale in South Carolina by numerous seed companies.  Questions exist among growers, consultants, and researchers 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.  Trial locations were selected based on previous and projected cotton acreage in a given area and differences in soil types and management inputs.   Large- and small-plot replicated trials were planted on the same day in the same field and managed with similar production practices.