<p style="text-align: justify;"><b>Field Testing</b></p>

<p style="text-align: justify;">Potato lines RBMT15-101, SEMT15-02 and SEMT15-15 were field tested in the United States (1994-1998) and Canada. Field evaluations determined that vegetative vigour, overwintering capacity, insect and disease resistance (except for resistance to CPB and PVY), tuber yield and quality characteristics remained unchanged in comparison to commercial varieties.</p>

<p style="text-align: justify;"><b>Outcrossing</b></p>

<p style="text-align: justify;">In general, the natural exchange of genetic material from potato is only possible with other varieties of potato (<i>Solanum tuberosum</i>). Since the reproductive characteristics of these transgenic potato lines were unchanged by the genetic modification, they should be no different than the respective parent cultivars &#39;Russet Burbank&#39; and &#39;Shepody&#39;.<br />
The chances for successful hybridization between the transgenic potato lines and most wild relatives is extremely unlikely as potatoes are unsuccessful in forming natural hybrids with the native or introduced weeds of Solanum species that do not bear tubers. In Canada there are no tuber producing wild relatives of Solanum. In the United States, tuber-bearing Solanum species include <i>S. jamesii</i>, <i>S. fendleri</i>, and <i>S. pinnatisectum</i>. However, the possibility of gene introgression is excluded due to constraints of geographical isolation and other biological barriers to natural hybridization. No natural hybrids have been observed between these species and cultivated potatoes in the United States.</p>

<p style="text-align: justify;">Field studies have shown that CPB and PVY resistance does not appear to be associated with increased weediness characteristics. Therefore, should CPB and PVY resistance genes be capable of introgression from these transgenic potatoes into wild species, the traits would be unlikely to provide a selective advantage sufficient to enable these hybrids to become serious weeds.</p>

<p style="text-align: justify;"><b>Weediness Potential</b></p>

<p style="text-align: justify;">Resistance to CPB and PVY infection will not, in itself, render potatoes weedy or invasive of natural habitats, since none of the reproductive or growth characteristics have been modified. Field data reports indicated no obvious differences in traits likely to provide a selective advantage such as the number of volunteers, emergence from seed potatoes, and disease and insect susceptibility (other than to target pests, CPB and PVY). Traditional resistance genes for CPB and PVY, and resistance genes for other insect pests, have been identified in potatoes and other Solanum species with no reports of increased weediness potential.</p>

<p style="text-align: justify;">Potatoes do not exhibit weediness characteristics and have difficulty becoming established outside cultivated fields. Small tubers left in the ground after harvest may give rise to volunteer plants in the next crop but are usually killed by frost or drought. Surviving volunteers can be controlled with herbicides and cultivation. Furthermore, seed dispersal is limited as dissemination is by tuber and seed. Outside of cultivated areas, seedlings grown from true seed do not compete successfully and are not reported as a weed pest.</p>

<p style="text-align: justify;"><b>Secondary and Non-Target Adverse Effects</b></p>

<p style="text-align: justify;">It was concluded that the genes inserted into the transgenic potato lines RBMT15-101, SEMT15-02 and SEMT15-15 would not result in any deleterious effects or significant impacts on nontarget organisms, including threatened and endangered species or beneficial organisms. The plant-pesticide Cry3A was previously approved in several CPB-resistant potato plants. Prior studies on the toxicity of Cry3A to mammals, allergenicity, and environmental fate data on the impact to avian species, nontarget and beneficial insects, honeybees and nontarget organisms, determined that Cry3A would not negatively impact non-target organisms or effect threatened and endangered species. Similarly, the PVY CP is found in all PVY-infected plants, and there are no reports of this protein (or PVY-infected plants) having any toxic effects. The NPTII protein is ubiquitous in the environment and was determined not to have potential for toxicity.</p>

<p style="text-align: justify;"><b>Impact on Biodiversity</b></p>

<p style="text-align: justify;">These potato lines have no novel phenotypic characteristics that would extend their use beyond the current geographic range of potato production. Since there is no occurrence of wild relatives of potato in Canada, there will be no transfer of novel traits to related species in unmanaged environments. Similarly, as the potential for gene transfer to tuber-producing wild relatives in the United States is very remote, it was determined that the risk of transferring genetic traits from RBMT15-101, SEMT15-02 and SEMT15-15 to species in unmanaged environments was insignificant.</p>

<p style="text-align: justify;"><b>Other Considerations</b></p>

<p style="text-align: justify;">In order to prolong the effectiveness of plant-expressed <i>Bt</i> toxins, and the microbial spray formulations of these same toxins, regulatory authorities in Canada and United States have required developers to implement specific Insect Resistant Management (IRM) programs. These programs are mandatory for all transgenic <i>Bt</i>-expressing plants and require that growers plant a certain percentage of their acreage with non-transgenic varieties in order to reduce the potential for selecting <i>Bt</i>-resistant insect populations. Details on the specific design and requirements of individual IRM programs are published by the relevant regulatory authority.</p>
