Gene escape from Bt talong could create problem weeds in the Philippines

Genetically engineered (GE) crops risk harm to the environment and our health. But exactly what are the dangers and how might they occur?

One danger often cited is that gene escape to wild populations could cause these populations to turn into more aggressive weeds. This could happen if certain GE crops (e.g. those with insect-resistance genes) are grown in places where local varieties (landraces) or wild (and weedy) relatives occur, for example in their centres of diversity. This danger might become a reality in the Philippines as GE insect-resistant Bt talong is released to the environment through open field trials.

The Philippines is part of the centre of diversity of eggplant.  The centre of diversity is where one finds the greatest diversity of cultivated types, landraces and wild relatives of a crop. For eggplant, the centre of diversity is thought to spread through the whole of Southeast Asia, from India to China and Indonesia (including the Philippines). Growing GE Bt talong in its centre of diversity, which includes the Philippines, spells bad news.

It is generally agreed that GE contamination is possible, even probable, especially in a centre of diversity. Conventional oilseed rape, maize, sunflowers, potato, sorghum, and many other crops can crossbreed with relatives that grow in their centre of diversity. It would seem likely, therefore, that GE crops would crossbreed with their relatives too, and would also pass on the GE gene to these relatives. Concerns regarding GE contamination of landraces are at the centre of Greenpeace’s campaign against GE maize in Mexico, because it is both a centre of origin and diversity for maize, and a staple crop for most Mexicans.

GE contamination is inevitable if GE crops are grown outdoors, even as field trials. We know that GE contamination of conventional, or non-GE, crops can happen as there are plenty of examples. There are also several examples of GE contamination from experimental field trials, where the GE crop has not been approved for growth or human consumption, yet it ends up in our food.

The additional risks associated with GE contamination from Bt talong within its centre of diversity  has largely been overlooked in the risk assessments for Bt talong, partly because little recent information exists. An independent study, commissioned by Greenpeace, finds that eggplant relatives do occur in the regions where the cultivation of Bt eggplant is proposed (in India and the Philippines), and that Bt eggplant may mate with these relatives to spread the Bt gene. The exact number of species that can breed with cultivated eggplant is not precisely known, but the report shows that there are at least 10 closely related species found in South and Southeast Asia that cultivated eggplant can mate with.

This new study has important implications. Concerns with crossbreeding and spreading of the GE gene through landrace populations and wild and weedy relatives include: food safety concerns; ecological effects; lack of GE-free choice; loss of biological and cultural heritage; and undermining of food security. One major fear is the possibility that the newly introduced GE gene will confer a selective advantage that might enable the plant to out-compete and overrun other natural vegetation. Insect-resistance is an example of such a trait, and has been engineered into GE talong as a “Bt” gene. Hence, should these wild or weedy relatives of eggplant acquire the Bt gene, it could result in talong becoming an aggressive and problematic weed that might wreak havoc in both agriculture and natural habitats.

GE crops should not be cultivated outdoors anywhere in the world, but if they are grown in their centres of diversity, the risks of outcrossing to relatives and spreading through populations of landraces, wild and weedy relatives and landraces are very real. The consequences of widespread contamination are potentially serious. Especially, as in the case of Bt talong, the insect-resistant GE genes are advantageous to a plant, and this risks creating problem weeds. Not to mention, potential health risks associated with the use of Bt gene technology.

Filipinos value wild species of eggplant for its curative and medicinal properties. No one knows what and how the Bt gene will affect the medicinal properties of eggplant, a long held traditional knowledge of Filipinos.

Greenpeace urges governments to employ the precautionary principle and not permit any authorisation of the outdoor cultivation of GE Bt talong, including field trials. The Philippines must protect its rich and diverse talong populations for Filipinos and future Filipinos.