The Political Economy of Regulation of Biotechnology in Agriculture - The Oxford Topic of Food, Politics, and Society - page 696

if grown within the crop's pollen dispersal range and if the two crops share the same
flowering time.28 Despite attempts at physical containment,29 it is generally accepted
that complete containment of pollen in male fertile lines is impossible. Therefore, genes
will move. How far and how fast will be determined by prevailing weather patterns and
conditions at the time pollen is shed, the method of pollen dispersal (for example, wind
or insects), the amount of pollen produced and its longevity, the distance between the
donor and compatible recipient, and whether the crop out-crosses or is self-pollinated.30
Gene exchange is the essence of the evolution of diversity and adaptation for living
organisms, a natural and ongoing process across millennia. The literature is consider-
able on natural rates of gene flow between compatible plant species; however, the poten-
tial for and extent of gene flow from transgenic to non-transgenic crops or to compatible
wild relatives is just beginning to be understood as are the potential ecological conse-
quences of these processes.
Gene flow from transgenic crops to non-GM counterparts has been confirmed in (1)
canola, an outcrossing, insect-pollinated species (e.g., Beckie et al. 2003; Damgaard and
Kjellsson 2005); (2) traditional landraces of maize in Mexico (Quist and Chapela 2001);
(3) weedy rice (red rice or shatter cane) from GM rice (Lu 2004); (4) non-GM maize
(Palaudelmas et al. 2009) (5) wild relatives of cotton (Wegier et al. 2011); (6) wild, weedy
relatives of sugar beet (Cureton et al. 2006; Fenart et al. 2009); and, most recently, (7)
non-GM wheat in Oregon. In the latter example, authorized GM wheat was grown in
test plots but was never released commercially (Ledford 2013). The source of the trans-
genes introgressed into formerly non-GM wheat is under investigation.31 Only genetic
testing can confirm whether or not introgression (genetic admixing) has occurred.
Humans as Vectors
Gene flow and adventitious presence are strongly affected by one vector in partic-
ular: humans. “Stealth seeds” are those seeds that find their way to the field, without
the benefit of any regulatory knowledge or approval, by the actions of people (Herring
2007). The spread of unauthorized GM seed can be rapid when the advantages, as per-
ceived by farmers, of having the transgenic seed outweigh the potential consequences of
planting it. Under this scenario, it becomes impossible to know the real adoption rate of
some GM crops or their spread within the farming community. It also becomes impos-
sible to keep them segregated from sexually compatible, non-GM crops (Herring 2013).
Herring (2007) describes the increasing presence of Bt cotton in Indian farmer's fields
that occurred prior to government approval of widespread planting. To slow down the
emergence of bollworms resistant to the Bt protein produced by the cotton plant, regu-
lators and seed producers mandate planting 10% of the field area to a non-transgenic
variety. In the “stealth seeds” scenario, no such precautionary steps were taken. Close
study of this situation may help researchers better understand the potential for boll-
worm resistance development and the extent of any gene flow from Bt cotton into
non-transgenic local varieties.