Researchers from the Peruvian National Institute for Agricultural Innovation (INIA) — which has been enforcing national and international policy on biosafety in agriculture since 1999 — have investigated claims that genetically modified maize (corn) is being farmed in the Barranca valley north of Lima (see http://go.nature.com/ijkpkz).

The INIA analysed the source and quantity of maize imports, records of seed cultivars, their genetic diversity and planting location. Samples were also tested from the Pativilca River basin — the main river in Barranca and its neighbouring valleys. These came from maize fields, local markets, a local collecting facility and seed companies that sell poultry feed.

Evidence of transgenes was discovered in only some of the poultry grain samples (full details are available in Spanish at http://go.nature.com/ikgyqj). This finding is not surprising. Peru imports about 1.5 million tonnes of maize grain annually — mainly for animal feed — from Argentina and the United States, where genetically modified maize is widely grown.

We believe that the Barranca region today is unlikely to be a primary centre of maize diversity. However, farmers there may be growing maize hybrids and other cultivars that have seeds of foreign origin.