Degree of Pollen Dispersal by Insects from a Field Test of Genetically Engineered Cotton

Abstract

This investigation was carried out to determine the movement of pollen from a field test site of genetically engineered cotton grown in 1989 at the Plant Science Research Farm of Mississippi State University. The objective was to evaluate the biosafety procedures used to reduce pollen movement. A field test of transgenic cotton measuring 136 by 30 m was bordered on all sides by 25 m of commercial cotton. All border rows were sampled from the lower, middle, and top fruiting positions of the plants. Seeds were analyzed for expression of the dominant selectable marker, neomycin phosphotransferase (npt II). Reliability of the assay was confirmed by polymerase chain reaction analysis. Results showed a consistent and significant reduction in pollen dissemination as distance from the test plot increased. Outcrossing went from 5 to <1% by 7 m away from the test plot. A low level of pollen dispersal of <1% continued to occur sporadically in the remaining border rows out to a distance of 25 m. No significant differences were noted for flower position on the plants, indicating there were no consistent seasonal effects on pollen dissemination. The border rows fulfilled their purpose of serving as a pollen sink to significantly reduce the amount of pollen dissemination from the test plot. At this location in Mississippi, the distance surrounding a transgenic cotton field test could be reduced and still provide reasonable pollen containment.