Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: A case study of GM maize gene flow in South Africa | Viljoen and Chetty Environmental Sciences Europe 2011 23 8 http content 23 1 8 o Environmental Sciences Europe a SpringerOpen Journal RESEARCH Open Access A case study of GM maize gene flow in South Africa Chris Viljoen1 Lukeshni Chetty2t Abstract Background South Africa has been growing first-generation commercial genetically modified GM maize since 1997. Despite a requirement for non-GM food especially for export there is no system for coexistence of GM and non-GM crop. Gene flow is a major contributor to commingling and different distances of cross-pollination have been recorded for maize using a variety of field-trial designs under different environmental conditions with the furthest distance being 650 m. However these trials have usually been small plots and not on the scale of commercial farming. There are also no published data regarding the extent of cross-pollination for maize in South Africa even after a decade of commercialization of GM. Thus the aim of this study conducted from 2005 to 2007 was to determine the extent of GM maize cross-pollination under South African conditions in the context of commercial farming practice. Materials and methods Field trials were planted with a central plot of yellow GM maize ha surrounded by white non-GM maize ha in two different geographic regions over two seasons with temporal and spatial isolations to surrounding commercial maize planting. Cross-pollination from GM to non-GM maize was determined phenotypically across 16 directional transects. Pollen counts during flowering were compared to weather data as well as percentage cross-pollination. The data were transformed logarithmically and mean percentage cross-pollination was compared to high cross-pollination. Results and discussion Although there was a general congruency between wind data pollen load and crosspollination it is evident that wind data and pollen load do not solely explain the directional extent of crosspollination and .
