34 CHAPTER 1
As can be seen in Table 1.3, the initial spread of Bt maize was quite slow
because of the scale-up time required to have a sufficient amount of seeds and to have the Bt trait inserted in hybrids that were suitably adapted to local conditions. Approval for commercial release of herbicide tolerance came in 2002 and the stacked traits of Bt and HT in 2007. Compared to cotton, the decrease in Bt and HT maize since the introduction of stacked maize was less pronounced. Bt remains the most popular trait, partly because especially white stacked maize adoption has been hindered by inadequate seed availability. In the 2008/09 production season, GM maize covered 70 percent of the total South African maize area, with Bt maize covering 43 percent. In 2009/10 the Bt maize area increased by a further 269,000 hectares up to 48 percent, mainly stemming from a drop in the white stacked maize area because of inadequate seed supply. Considering the adoption rates illustrated in Table 1.3, it is possible to con-
clude that South African maize farmers have benefited from the introduction of GM maize. Similar to the indicated GM cotton adoption rates in Table 1.1, these GM maize adoption rates represent adoption by predominantly com- mercial farmers. There are no official smallholder GM maize adoption figures, but it is estimated that about 10,500 subsistence, smallholder, and emergent farmers (about 23 percent of the smaller farmers), buying hybrid seed from the three major seed companies, planted GM maize in 2007 (Gouse, Kirsten, and Van der Walt 2008). However, there are still areas in South Africa where small- holders plant mainly open-pollinated varieties and traditional/saved seed, and definitions of subsistence, smallholder, smallholder projects, and emerging farmers also complicate estimations. It can therefore be argued that the num- ber of smallholders planting GM maize is still relatively minimal. Marra, Pardey, and Alston (2002) found that there were significant ben-
efits to planting Bt maize in the United States through increased yields, even when it appeared as if borer infestation levels were not large enough to con- trol with insecticides. Marra, Carlson, and Hubbell (1998) reported that the use of Bt maize boosted yields by 4–8 percent, depending on location and year. Results from outside the United States show a similar pattern. In the Huesca region in Spain, Brookes (2002) reported a yield increase of 10 percent over conventional maize protected with pesticides and an increase of 15 per- cent when insecticides were not used. Other regions in Spain enjoyed an aver- age Bt yield advantage of 6.3 percent, with a range of 2.9–12.9 percent. James (2002) reported a 8–10 percent yield increase in Argentina up to 2004, and more recent studies show a 5–6 percent increase (Brookes and Barfoot 2008). Gonzales (2002) recorded a yield advantage of 41 percent for Bt maize on
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