ABSTRACT

Potential pollen dissemination from transgenic cotton fields has implications in breeding, seed production, seed certification, and regulatory disciplines. The purpose of this study was to evaluate pollen dispersal from transgenic fields to conventional fields in commercial seed production environments in Arizona, Mississippi, and Texas. Roundup Ready rolled towel bioassays and enzyme-linked immunosorbent assays were used to quantify the presence of transgenes in seeds harvested from conventional fields. A 55-foot non-planted buffer was effective in maintaining 100% varietal purity in a conventional field in Arizona. In Mississippi, seeds harvested in a conventional field at distances of 12 ft or more from a RR pollen source had similar levels of adventitious presence as the parental source seed. Pollen dispersal was greatest in the Texas environment, plus pollen dispersal varied between locations within a conventional field at 10 ft and 20 ft from the RR pollen source. Transgenic percentage in seed harvested from conventional fields dropped sharply from 3 ft to 50 ft from the transgenic pollen source, and then leveled off at distances greater than 50 ft at a transgenic percentage similar to parental seed across production environments. The results from these studies indicate that pollen dispersal from transgenic cotton fields can be effectively managed using field isolations using a combination of unplanted areas and unharvested border rows. A 50 ft isolation provided adequate control of pollen dispersal across production environments evaluated in these studies.