Agriculture Reference
In-Depth Information
transgenes in wild populations; (3) understanding the consequences of gene flow, such
as fitness effects, impacts on plant community structure, and variations in these for dif-
ferent constructs; (4) developing biological containment strategies and evaluating their
stability, such as auto-suicidal mechanisms, tissue-specific excision, gene silencing, and
chloroplast transformation; (5) new means of physical confinement, such as trap-crop
border rows, (6) means to mitigate effects and slow the spread or limit expression of the
transgenes, and (7) longer-term monitoring. Information obtained from these research
efforts are needed to develop robust coexistence policies. In the EU, CoXtra was initi-
ated to address many of these issues in efforts to develop and support a robust co-exis-
tence policy for the European Union.33
Adventitious Presence
A key aspect of co-existence is the ability of organic and non-GM practitioners to pre-
serve the genetic identity of their seed and produce along the commodity chain (identity
preservation). Even without hybridization (gene flow), adventitious presence of GM in
non-GM seed stocks can readily occur. Adventitious presence refers to the presence of
any unwanted material that becomes mixed with seeds at any point along the commod-
ity chain (e.g., weed seeds, stones, insect parts, and the like). Farmers and food pro-
cessors accept a low level of adventitious material as unavoidable. But the adventitious
presence of GM seed presents serious challenges for producers and processors—espe-
cially for the organic food industry—who want to ensure they retain their price pre-
mium and that they provide GM-free foods to their customers.
On farms, GM and non-GM seed can be commingled during sowing, crop produc-
tion, harvesting, post-harvest handling, and storage (Figure 28.1, Devos et al. 2007). If
a GM farmer also grows non-GM crops on the land and uses the same equipment for
planting and harvesting and the same storage facilities for both types of seeds, com-
mingling of GM and non-GM seed can occur. Unintentional movement of GM seed
between farms can also occur if machinery is shared and the machinery is not properly
cleaned between operations. Residual seed in storage areas, vehicles used to transport
seed, and seed at processing plants can all contribute to the adventitious presence of
GM in non-GM seed and products. Thus, at many points along the commodity chain,
organic and non-GM seed could become mixed with GM seed and lead to a positive test
for the presence of the GM seed.
The extent of the problem of keeping GM seeds separate from organically grown and
non-GMO seeds34 was not fully realized until the US “Starlink” maize incident of 2000
(Schurman and Kelso 2003). “Starlink” was a maize hybrid genetically modified to be
resistant to lepidopteron pests, specifically the European corn borer. It contained the
cry 9C gene, a gene that codes for an insecticidal protein that is derived from the soil
bacterium, Bacillus thuringiensis (Bt). The resulting protein produced has insecticidal
activity against the Lepidoptera. “Starlink” had been approved by the EPA for use as ani-
mal feed only.35 The EPA and other regulatory agencies were confident that animal feed
Search WWH ::




Custom Search