Philip J. Jones
University of Reading, UK
Maria de Fátima Quedas
Instituto Politécnico de Santarém, Portugal
Richard B. Tranter
University of Reading, UK
Carlos P. Trindade
Instituto Politécnico de Santarém, Portugal

After 10 years of GM maize cultivation in Portugal, the area produced remains modest, at 6.3% of total maize production in 2015. This fact suggests that significant constraints to further expansion continue to exist. Through a survey of the structural and attitudinal characteristics of GM and conventional maize producers, this article explores constraints to adoption of GM crops in Portugal. The survey revealed a complex mix of barriers based around structural and attitudinal factors. For example, GM adopters managed larger farms than conventional, with double the area of maize grown. GM maize growers felt more constrained (in terms of factors depressing yields) by pests, especially corn borers and weeds than their non-GM counterparts. A number of non-structural barriers to GM uptake were also identified, such as perceived public opposition to GM cultivation and increased management burden associated with coexistence measures, through the requirement to make decisions in conjunction with neighbors.

Key words: Barriers to uptake, coexistence measures, GM maize.