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

<p style="text-align: justify;">Species sexually compatible with rice occur in most rice producing areas, especially those within the centre of origin of the cultivated species. In the United the only species known to be compatible with cultivated rice are <i>O. rufipogon</i>, which has been found in a single location in the Everglades of Florida, and red rice (<i>O. sativa</i> ssp.). Due to the relative isolation of <i>O. rufipogon</i>, it is unlikely to hybridize with cultivated rice. Cross-pollination may, however, occur with red rice, under suitable conditions, and form imazethapyr-tolerant hybrids.</p>

<p style="text-align: justify;">PWC16 has not been modified for cultivation in areas outside of its adapted range. Thus, in areas such as Canada, any unintentional release would not be of concern. Species sexually compatible with cultivated rice do not occur in Canada and any seeds unintentionally released in the environment would not persist due to the unfavourable climate.</p>

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

<p style="text-align: justify;">Cultivated rice can become a weed in certain areas where it is grown. PWC16 has not demonstrated characteristics that would confer any competitive advantage, other than tolerance to imazethapyr. Vegetative vigour, time to maturity and seed production of PWC16 were within the normal range of expression of these traits expressed by currently commercialized rice varieties. Tolerance to an herbicide does not, in itself, increase the potential for rice to become weedy or invasive of natural habitats. In the event of the formation of an herbicide tolerant hybrid, there would be no competitive advantage conferred on any hybrid progeny in the absence of sustained imazethapyr use. The imazethapyr-tolerant plant could be controlled by cultural or mechanical means, or by using herbicides other than imazethapyr. PWC16 would not be expected to express greater weediness characteristics than commercial rice varieties.</p>

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

<p style="text-align: justify;">The characterization of the modified AHAS gene containing a single base pair change, and the resulting modified enzyme led to the conclusion that the expression of the modified AHAS does not result in altered toxic or allergenic properties. The AHAS enzyme is not a known toxin, does not confer resistance to agricultural pests and is present in plants and micro-organisms with a history of safe use. Based on this information, it was determined that PWC16 will not result in altered impacts on non-target organisms, compared to conventional rice varieties.</p>

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

<p style="text-align: justify;">PWC16 has no novel phenotypic characteristics that would extend its use beyond the current geographic range of rice production. The novel herbicide-tolerant trait could, however, be transferred to unmanaged areas in the United States where species sexually compatible with cultivated rice occur. The herbicide-tolerant trait, in itself, will not render any hybrids weedier than conventional rice-wild species hybrids. The line has also been found safe to non-target organisms and did not display altered plant pest potential since the agronomic and biological characteristics were within the normal range of conventional rice varieties. Furthermore, the novel herbicide-tolerant trait has not altered the ability of PWC16 to persist in areas outside of rice growing areas, such as Canada.</p>
