Excerpts from the report: Acala 1517D and Pima S-2 are new varieties of cotton that have been developed very recently through research on G. hirsutum and G. barbadense, respectively. At present, spindle-type mechanical harvesters have virtually replaced hand pickers. Experimental high-capacity roller gins have been made in the laboratory and by manufacturers of gin machinery and are now in commercial use. In the ginning and marketing of cotton, there has been an increase in roller ginning of first-picked, handpicked upland cotton. This has been done to provide industry with several thousand bales of high-grade upland fiber that has relatively few neps and that can command a premium to offset the relatively high cost of ginning with the roller gins. On the other hand, several thousand bales of late, rough-harvested and ground-harvested, low-grade Pima cotton recently have been saw ginned. Consequently, to provide up-to-date information on recent developments and practices in the ginning of cotton in the Southwest, this report describes the results of comprehensive tests among three types of cotton gins used in the ginning of two new varieties of cotton picked during three harvest periods. Differences are reported in measurements of ginning performance, cottonseed, fiber qualities, spinning performance, and spinning qualities.