A subset of 130 landraces were planted at a winter nursery at Tecoman, Colima, Mexico along with a set of 85 newly collected accessions from Mexico. In this environment more landraces reached maturity and set seed. This planting was replicated in Shafter, CA in 2005 to assess environmental effects on morphological traits. Over 30 traits were scored on plants of each landrace. Some traits may have potential for cultivar improvement and are important for conservation. This data will be used for cluster analyses to show overall similarities and degree of divergence among the landraces. The overall diversity and specific trait diversity would be useful information for the identification of germplasm sources to be used in cultivar improvement. More detailed analyses of the genetic diversity will involve the use of PCR based microsatellite markers from newly developed at the Cotton Enhancement Program Shafter CA and public domain. These locus specific markers are selected to enable a genetic map based assessment of the genetic diversity in the landraces. The use of molecular markers is expected to reveal more variation not evident from the physical traits, and will become a valuable tool in the maintenance and utility of the diversity of the germplasm collection.