Abstract: The genetically modified (GM) crops have been globally commercially cultivated for 20 years, and public concerns are persistent overheating about ecological risk of gene flow. This study investigated the pollenmediated gene flow (PGF) frequency of Cry1Ac from transgenic cotton SGK321 (Cry1-Ac/CpTI) to nontransgenic cottons Shiyuan 321 and Zhongmian 35 under three wind conditions (0.54, 0.92 and 1.27 m·s^-1) in greenhouses by PCR and Bt protein assays. Our results revealed that PGF varied depending on the wind speed when Shiyuan 321 was the pollen receptor, and was the highest under low speed wind and the lowest under high speed wind. With Zhongmian 35 as pollen receptor, PGF was very low, and not dependent on the wind speed. PGF depended on the variety of pollen receptors, and total PGF to pollen receptor of Shiyuan 321 (GM parental line) (10.63%) was higher than that of Zhongmian 35 (2.50%). PGF declined exponentially with increasing distance between GM cotton and nonGM receptors. Our research provided some reference for ecological safety assessment of windmediated gene flow.

Key words: urease activity, Loess Plateau, soil, alkaline phosphatase activity, microbial biomass carbon and nitrogen, invertase activity