UCS is concerned about the engineered squash because it believes that it poses environmental risks at commercial scale. These risks fall into three categories. The first is that the virus-resistance genes may flow from engineered squash to wild relatives and negatively impact the wild relatives. This issue is important because this country is home to important populations of wild squash and is considered a center of diversity for squash. Because they harbor wild relatives and traditional varieties of a crop, centers of diversity contain significant genetic diversity that may be important for crop improvement.
Plant breeders rely on centers of diversity for genes to fortify crops.
Gene flow also becomes an international risk issue because Mexico is a center of squash diversity. Transgenic squash may threaten wild populations in Mexico if the seeds enter international commerce. Second, the engineered squash may become a weed. Third, new viral strains may be created as a result of interactions between the virus genes in the squash and genes of other viruses that may infect the squash. We cannot say that these risks are serious but we can say that they should be evaluated.