The average FPD at a distance of 1 m from the dyed Bt cotton plot to its east, south, west and north was estimated to be 44.8%, 48.9%, 57.1% and 21.5%, respectively, and declined with increasing distance in the four directions.

• 靠近转Bt基因棉花粉染色区1m处的平均花粉散布频率；在东、南、西、北4个方向分别为44.；8%25、48