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

<p style="text-align: justify;">The maize line DLL25 was field tested in the major maize growing regions of the United States starting in 1991, in Canada since 1994, and in Argentina. DLL25 has been evaluated extensively in the laboratory, greenhouse, and field experiments. The transgenic maize was compared to non-transgenic counterparts for agronomic characteristics including test weight, dropped ears, stalk lodging, barrenness, stay green, seedling vigour, plant height, ear height, growing day units to 50% pollen shed, growing degree day units to 50% silk emergence, silk delay, green snap, maturity, yield, grain moisture, disease and insect susceptibilities. Field data determined that vegetative vigour, flowering period, time to maturity, seed production, and disease and insect susceptibilities were within the normal range of expression currently displayed by commercial maize hybrids. Overall the field data reports and data on agronomic traits showed that maize line DLL25 had no potential to pose a plant pest risk.</p>

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

<p style="text-align: justify;">Since pollen production and viability were unchanged by the genetic modification resulting in maize line DLL25, pollen dispersal by wind and outcrossing frequency should be no different than for other maize varieties. Gene exchange between maize line DLL25 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 few plant species closely-related to maize in the wild, the risk of gene flow to other species is remote. Cultivated maize, <i>Zea mays</i> L. subsp. mays, is sexually compatible with other members of the genus Zea, and to a much lesser degree with members of the genus Tripsacum.</p>

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

<p style="text-align: justify;">No competitive advantage was conferred to maize line DLL25 other than that conferred by resistance to glufosinate ammonium herbicides. Resistance to glufosinate ammonium will not, in itself, render maize weedy or invasive of natural habitats since none of the reproductive or growth characteristics were modified.<br />
Cultivated maize is unlikely to establish in non-cropped habitats and there have been no reports of maize surviving as a weed. In agriculture, maize volunteers are not uncommon but are easily controlled by mechanical means or by using herbicides, other than glufosinate ammonium. <i>Zea mays</i> is not invasive and is a weak competitor with very limited seed dispersal.</p>

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

<p style="text-align: justify;">It was determined that genetically modified maize line DLL25 did not have a significant adverse impact on organisms beneficial to plants or agriculture, or nontarget organisms, and was not expected to impact on threatened or endangered species. The PAT enzyme responsible for glufosinate ammonium tolerance does not possess mammalian toxicity. The PAT enzyme has a very specific enzymatic activity, does not possess proteolytic or heat stability typical of toxic compounds, and does not affect the metabolism of the plant.</p>

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

<p style="text-align: justify;">DLL25 has no novel phenotypic characteristics that would extend its use beyond the current geographic range of maize production. Since the risk of outcrossing with wild relatives in the United States and Canada is remote, it was determined that the risk of transferring genetic traits from DLL25 maize lines to species in unmanaged environments was not a significant concern. It was determined that the overall relative impact on plant biodiversity was neutral, as was the impact on animal and microbe biodiversity since the introduced PAT enzyme was not expected to alter the plant&#39;s metabolism and as such, novel compounds would not be produced.</p>
