Thus, this study aimed to test the effectiveness of high crop bar-rier (around 3 m high Sorghum) in reducing gene flow from GMyellow kernel to non-GM white kernel maize and the maximumdistance of pollen flow and cross-pollination of maize in large fields.Maize is monoecious and diclinous and easy to cross-pollinated asit is protandrous, with pollen being shed before the pistils beingreceptive. Although maize pollen grains are relatively large andheavy, they can disperse long distance on the airflow in case ofsuitable meteorological conditions.