Pollination Competition Effects on Gene‐Flow Estimation: Using Regular vs. Male‐Sterile Bait Plants

Abstract

Pollen‐mediated gene flow from transgenic crops is a concern of the scientific community as well as the general public. Although a common practice, the use of male‐sterile bait plants in field trials to demonstrate rates of gene transfer has been questioned due to the lack of pollination competition. However, little direct evidence has been published. Field experiments of male‐sterile and male‐fertile corn bait plants were conducted in 2001 and 2002, respectively, to evaluate the effects of pollination competition on gene‐flow assessment. Male‐sterile bait plants exhibited a significantly higher rate of outcrossing than male‐fertile plants. The results obtained from this study suggest that actual gene flow from transgenic plants to their wild‐type cultivars or relatives is likely to be lower than estimates reported in previous studies using male‐sterile bait plants, and that male‐fertile that is, normal, bait plants should be used in future studies attempting to estimate gene flow.