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

<p style="text-align: justify;">Event 3272 maize hybrids were tested at 8 locations in 2003 and 17 locations in 2004 in the United States corn belt. A total of 26 agronomic traits were evaluated. These agronomic traits covered a broad range of characteristics that encompass the entire life cycle of the maize plant and included data assessing seedling emergence, vegetative vigour, basic morphology, growth habit, time to reproduction, susceptibility to European corn borer and gray leaf spot, and yield characteristics. Event 3272 is not expected to exhibit modified response to diseases and pest insects, compared to unmodified corn counterparts, as the expression of the AMY797E alpha-amylase and PMI phosphomannose isomerase is unrelated to plant pest potential. For the majority of agronomic traits, no statistically significant differences between Event 3272 hybrids and their non-transformed isogenic counterparts were observed.</p>

<p style="text-align: justify;">Although instances of statistically significant differences between Event 3272 and control hybrids were observed for some traits, there were no consistent trends in the data across locations, hybrids or years, that would indicate that any of these differences were due to the genetic modification. Susceptibility to the European corn borer (ECB) could not be thoroughly evaluated due to very low ECB infestation levels. Similarly, susceptibility to Northern corn leaf blight, Southern corn leaf blight, and other diseases could not be evaluated due to a lack of naturally present disease inoculum. However, no change in response to pests or pathogens is anticipated from the expression of the AMY797E and PMI proteins in Event 3272. Furthermore, trial observations showed that susceptibility of Event 3272 hybrids to gray leaf spot disease is unchanged compared to control hybrids. The results showed no biologically meaningful differences between Event 3272 hybrids and their isogenic non-transgenic counterparts.</p>

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

<p style="text-align: justify;">The data included in the submission indicated that as pollen production and viability were unchanged by the genetic modification resulting in Event 3272, pollen dispersal by wind and outcropping frequency should be no different to other maize varieties. Gene exchange between Event 3272 and other cultivated maize varieties will be similar to that which occurs naturally between cultivated maize varieties at the present time. In the United States and Canada, where there are no plant species closely-related to maize in the wild, the risk of gene flow to other species appears remote.<br />
Maize (<i>Zea mays</i> ssp. <i>mays</i>) freely hybridizes with annual teosinte (<i>Zea mays</i> ssp. <i>mexicana</i>) when in close proximity. These wild maize relatives are native to Central America and are not present in the United States or Canada, except for special plantings. <i>Tripsacum</i>, another genus related to <i>Zea</i>, contains sixteen species, of which twelve are native to Mexico and Guatemala. Three species of <i>Tripsacum</i> have been reported in the continental United States: <i>T. dactyloides</i>, <i>T. floridanum</i> and <i>T. lanceolatum</i>. Of these, <i>T. dactyloides</i>, Eastern Gama Grass, is the only species of widespread occurrence and of any agricultural importance. It is commonly grown as a forage grass and has been the subject of some agronomic improvement (i.e., selection and classical breeding). <i>T. floridanum</i> is known from southern Florida and <i>T. lanceolatum</i> is present in the Mule Mountains of Arizona and possibly southern New Mexico. Even though some <i>Tripsacum</i> species occur in areas where maize is cultivated, gene introgression from maize under natural conditions is highly unlikely, if not impossible. Hybrids of <i>Tripsacum</i> species with <i>Zea mays</i> are difficult to obtain outside of the controlled conditions of laboratory and greenhouse. Seed obtained from such crosses are often sterile or progeny have greatly reduced fertility.</p>

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

<p style="text-align: justify;">Unmodified plants of <i>Zea mays</i> are not invasive of unmanaged habitats in the United States or Canada. Maize does not possess the potential to become weedy due to the lack of seed dormancy, the non-shattering nature of corn cobs and the poor competitive ability of seedlings. According to the information gained from the field trials, Event 3272 was determined to be similar to unmodified maize in this respect. No competitive advantage was conferred to Event 3272 by the expression of the AMY797E and PMI proteins. The introduction of these novel traits did not make Event 3272 maize weedy or invasive of natural habitats since none of the reproductive or growth characteristics were modified, and tolerance to disease was unchanged. It was concluded that Event 3272 has no increased weediness or invasiveness potential compared to currently commercialized corn varieties.</p>

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

<p style="text-align: justify;">The AMY797E protein is not homologous to known toxins. A single-dose oral toxicity study showed that the AMY797E protein is not toxic to the mouse at a dose of 1,511 mg/kg body weight. This dose represents about 2.1 times the worst-case daily dietary dose for rodents eating a diet comprising 100% kernels of maize Event 3272 in the field. Alpha-amylases of varying degrees of amino-acid homology with AMY797E protein occur widely in nature among prokaryotes and eukaryotes. Alpha-amylase enzymes are present in plants, including maize. Alpha-amylase enzymes are also found in human saliva. There is an enormous diversity of alpha-amylases in soil microorganisms, including many heat-stable alpha-amylases. Therefore, it is likely that mammals, birds, insects and microorganisms exposed to AMY797E protein expressed in Event 3272 have had prior exposure to alpha-amylases. No harmful effects of such exposure is known.</p>

<p style="text-align: justify;">Furthermore, as the AMY797E protein is not detectable in pollen of Event 3272, this maize poses no risk to pollinators and non-target pollen consumers. The kernel-specific expression of the protein in Event 3272, the lack of detectable mammalian toxicity of AMY797E, and the weight of evidence that alpha-amylases are not toxic to other wildlife, indicates minimal risk to non-target organisms resulting from exposure to AMY797E protein in Event 3272.</p>

<p style="text-align: justify;">Phosphomannose isomerase is a ubiquitous enzyme involved in carbohydrate metabolism. Phosphomannose isomerases of varying degrees of amino acid homology to PMI expressed in Event 3272 occur widely in nature and have been detected in some crop species, mammals, humans, yeast, fungi and bacteria. Species that will be exposed to PMI from Event 3272 tissues are highly likely to have prior exposure to similar PMI proteins. No harmful effects of such exposure are known or expected. The PMI protein expressed in Event 3272 is not homologous to any known toxins and the bacterially-expressed PMI protein showed a lack of acute toxicity to the mouse at a single oral dose of 3,080 mg PMI/kg body weight. Based on this evidence, no adverse effects on organisms exposed to the PMI protein expressed in Event 3272 are anticipated.</p>

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

<p style="text-align: justify;">Event 3272 has no novel phenotypic characteristics that would extend its range beyond the current geographic range of maize production. Event 3272 is not more weedy or invasive than conventional maize and, since maize has no wild relatives with which it can outcross in the United States and Canada, there will be no transfer of the novel traits to other species in unmanaged environments. In addition, the novel traits were determined to pose minimal risk to non-target organisms and no changes to agronomic practices typically applied in management of conventional maize are required for Event 3272. Specifically, no increases in pesticides and fertilizers are required as well as no changes in cultivation, planting, harvesting or volunteer control. Thus, potential impacts on biodiversity are not expected to be different to the cultivation of conventional maize hybrids.</p>
