Identification of High-Quality Testing Locations for Cotton Performance Trials.

Performance yield trials are some of the most expensive processes in a cotton breeding program. Cotton plots require a great deal of land, agronomic inputs, and plot-sample processing.  Much of the equipment is expensive and specialized such as the harvesters, gins, and fiber measurement devices.  Therefore it is important to only test strains and cultivars in the most distinguishing environments. Traditionally the best testing environment has been in the Mississippi Delta near Greenville, MS.  More recently it has been thought that growing environments in Australia are allowing breeders there to distinguish high-yielding, broadly adapted genotypes. The program of the Cotton Improvement Lab at Texas A&M University in College Station, TX, regularly conducts performance trials throughout Central and South Texas. Several stability tests such as the ‘cultivar superiority measure’, ‘ecovalence’ and stability variance’ were used in AgroBase to determine stability. Biplot analysis was also used to characterize testing locations. Based on data collected over the last seven years from the commercial variety tests, it was concluded that the high-yielding locations at Weslaco and College Station are the best locations at identifying cultivars with the highest yield potential, but many of the dryland locations are better locations for determining stable and repeatable fiber qualities.