Peer-reviewed surveys indicate positive impact of commercialized GM crops

319 The results show the variability of benefits from region to region and year to year. A survey of Indian cotton farmers in crop harvest years 2005–2006 through 2007–2008 showed that Bt cotton growers in Gujarat had larger yield improvements than their counterparts in Maharashtra, with the former obtaining 82–150% greater yields, whereas the latter obtained only 24–40% higher yields. Smallholders in KwaZulu Natal, South Africa, who were surveyed from harvest years 1998–1999 to 2000–2001 reported a yield benefit associated with Bt cotton between 56% and 85%, which is attributed to variable weather conditions and pest pressure from year to year. It is important to note that the analysis of yield differences is complicated by differences in yield potential and other characteristics of background germplasm that may differ between the varieties that are available with and without the engineered trait. For example, the first Bt cotton varieties to be approved for commercialization in India had been in the regulatory pipeline for several years, during which time conventional breeding had continued to produce varieties with superior yields and disease resistance. These earliest official varieties were known to be susceptible to wilt when subjected to early moisture stress, which may have driven the negative results observed Peer-reviewed surveys indicate positive impact of commercialized GM crops