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

<p style="text-align: justify;">The transgenic cotton lines 531, 757 and 1076 were field tested in the United States (1990-1994). Agronomic characteristics such as yield, boll size, plant vigour, growth, morphology, germination and flowering, were compared to those of unmodified cotton counterparts and were shown to be within the range of non-transformed cotton lines. Stress adaptation was evaluated, including susceptibility to various pests and pathogens. Susceptibilities to diseases such as bacterial blight, boll rot, Fusarium, Phymatotricum root rot, and verticillium wilt were unchanged. Processing qualities of cotton lint such as micronaire, length, strength and elongation were compared. The observed variability was within the range of inherent variability of cotton varieties and was not attributed to the inserted genes. Reports demonstrated that the cotton lines 531, 757 and 1076 did not exhibit weedy characteristics and had no effect on nontarget organisms or the general environment relative to conventional cotton varieties.</p>

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

<p style="text-align: justify;">Cotton (<i>Gossypium hirsutum</i>) is mainly a self-pollinating plant, but insects, especially bumblebees and honeybees, also routinely transfer pollen. The pollen is heavy and sticky and the range of natural crossing is limited. Outcrossing rates of up to 28% to other cotton cultivars have been observed under field conditions and decline rapidly with distance from the pollen source. Given proximity and the availability of insects as pollen vectors, transgenic cotton lines 531, 757 and 1076 are likely to hybridize with other cotton varieties.</p>

<p style="text-align: justify;">In the United States, compatible species include <i>G. hirsutum</i> (wild or under cultivation), <i>G. barbadense</i> (cultivated Pima cotton), and <i>G. tomentosum</i>. There are no wild relatives or wild populations of cotton in Canada that can naturally hybridize with <i>G. hirsutum</i>. It was reported that gene movement from <i>G. hirsutum</i> to <i>G. barbadense</i> may be possible given suitable conditions, while gene transfer to <i>G. tomentosum</i> is less probable due to chromosomal incompatibility and non-synchronous flowering periods. Overall, the probability of gene transfer in unmanaged ecosystems is unlikely due to the relatively isolated distribution of Gossypium species, different breeding systems, and genome incompatibility. Hybrids resulting from artificial crosses between cotton and wild species are generally sterile, unstable and of poor fitness</p>

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

<p style="text-align: justify;">The Cry1Ac or NPTII encoding genes were not expected to confer an ecological advantage to transgenic cotton lines 531, 757 and 1076 and their potential hybrid offspring. Resistance to kanamycin and specific lepidopteran insects will not render cotton weedy or invasive of natural habitats since none of the reproductive or growth characteristics have been modified. Field trial reports indicated that traits which may confer a selective advantage, such as increase in volunteers from seed, regrowth from stubble, or increase in seed dormancy in cotton lines 531, 757 and 1076 were equivalent to non-modified varieties.</p>

<p style="text-align: justify;">There are no specific problems with cotton as a weed. Cottonseed may remain in the field after harvesting and germinate under favorable conditions. Seeds may also survive mild and dry winters. Suitable treatments for any volunteers in the next crop include cultivation and the use of herbicides.</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 introduction of the Cry1Ac and NPTII encoding genes into transgenic cotton lines 531, 757 and 1076 would not result in any deleterious effects or significant impacts on nontarget organisms, including those that are recognized as beneficial to agriculture and those that are recognized as threatened or endangered in the United States and Canada.</p>

<p style="text-align: justify;">The novel proteins, Cry1Ac and NPTII, expressed in these cotton lines are not known to have any toxic properties on any nontarget organisms. The lack of known toxicity for these proteins and the low levels of expression in plant tissue suggest no potential for deleterious effects on beneficial organisms such as bees and earthworms.</p>

<p style="text-align: justify;">The insecticidal protein was shown to be active on only lepidopteran species, even when fed at levels that were well above the concentrations that were effective on target species. Host range specificity was similar for the native and synthetic proteins. Tobacco hornworm was the most sensitive species and tobacco budworm, corn earworm and European corn borer were relatively less sensitive. The test system included six non-target species representing the orders Coleoptera, Diptera, Orthoptera and Homoptera (boll weevil, Southern corn rootworm, Colorado potato beetle, yellow fever mosquito, German cockroach and green peach aphid).</p>

<p style="text-align: justify;">Dietary toxicity studies were performed using the microbial protein on beneficial insects (honeybee, ladybird beetle, green lacewing larvae and parasitic wasp). No effect was observed on non-target insects at concentrations more than 100 fold higher than those used to control target insects.</p>

<p style="text-align: justify;">Acute oral and short-term studies were undertaken with albino mice and bobwhite quail. After 8 days there were no observable effects on mice fed the insecticidal protein at the highest dose of 4,000 mg/kg body weight. Raw cottonseed was fed at up to 100,000 ppm to bobwhite quail with no observed effects. These observations were expected, as the novel proteins are rapidly inactivated in simulated mammalian stomach fluids by enzymatic degradation and pH-mediated proteolysis. The proteins expressed in transgenic cotton lines were shown to be equivalent to the original microbial proteins produced by the common soil <i>B. thuringiensis</i> subsp. <i>kurstaki</i> bacteria.</p>

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

<p style="text-align: justify;">The transgenic cotton lines 531, 757 and 1076 had no novel phenotypic characteristics that would extend their use beyond the current geographic range of cotton production. Since there is no occurrence of wild relatives of cotton in Canada, there will be no transfer of novel traits to unmanaged environments. Similarly, as the risk of gene transfer to wild relatives in the United States is very remote, it was determined that the risk of transferring genetic traits from cotton lines 531, 757 and 1076 to species in unmanaged environments was insignificant.</p>
