Detection of Transgenes in Local Maize Varieties of Small-Scale Farmers in Eastern Cape, South Africa

Abstract

Small-scale subsistence farmers in South Africa have been introduced to genetically modified (GM) crops for more than a decade. Little is known about i) the extent of transgene introgression into locally recycled seed, ii) what short and long-term ecological and socioeconomic impacts such mixing of seeds might have, iii) how the farmers perceive GM crops, and iv) to what degree approval conditions are followed and controlled. This study conducted in the Eastern Cape, South Africa, aims primarily at addressing the first of these issues. We analysed for transgenes in 796 individual maize plants (leaves) and 20 seed batches collected in a village where GM insect resistant maize was previously promoted and grown as part of an governmental agricultural development program over a seven year period (2001–2008). Additionally, we surveyed the varieties of maize grown and the farmers’ practices of recycling and sharing of seed in the same community (26 farmers were interviewed). Recycling and sharing of seeds were common in the community and may contribute to spread and persistence of transgenes in maize on a local or regional level. By analysing DNA we found that the commonly used transgene promoter p35s occurred in one of the 796 leaf samples (0.0013%) and in five of the 20 seed samples (25%). Three of the 20 seed samples (15%) included herbicide tolerant maize (NK603) intentionally grown by the farmers from seed bought from local seed retailers or acquired through a currently running agricultural development program. The two remaining positive seed samples (10%) included genes for insect resistance (from MON810). In both cases the farmers were unaware of the transgenes present. In conclusion, we demonstrate that transgenes are mixed into seed storages of small-scale farming communities where recycling and sharing of seeds are common, i.e. spread beyond the control of the formal seed system.

Pollen-mediated gene flow and seed exchange in small-scale Zambian maize farming, implications for biosafety assessment

“…Ghana and South Africa have similar features in their small-scale farming systems, e.g. less than 10 m separation of maize fields and recycling of seeds 40 61 62 .…”

Social Impacts of GM Crops in Agriculture: A Systematic Literature Review

“…The iterative searches showed that while some papers of relevance to the topic (such as [28][29][30][31][32][33][34][35][36][37]) were indeed not captured in the search, these were sufficiently few not to challenge the overall findings presented here and did not address other topics than those also addressed in the reviewed literature. The iterative searches also showed that in particular, literature addressing cultural heritage impacts of GM crops in agriculture fell outside the search.…”

“…The iterative searches also showed that in particular, literature addressing cultural heritage impacts of GM crops in agriculture fell outside the search. Examples of relevant studies are [32][33][34][35][36][37]. However, even taking into account the additional papers found in the iterative searches, such studies remain few in comparison with the other impact groups (see Section 3.2).…”

Capacity building for genetically modified organism (GMO) detection in West Africa: Identifying a circulating GMO maize variety in Mali

“…However, the 35s promoter sequence from the Figwort mosaic virus (FMV) was not amplified for the 15 varieties. In South Africa, 10% of varieties contained genes for insect resistance and 15% were associated with herbicide tolerant events (Iversen et al, 2014). These data along with the identification of a transgenic dark seeded maize variety from Mali would suggest additional screening of maize germplasm from Mali should be conducted.…”