英文文献：Economic Performance of Bt Cotton Varieties in Pakistan-巴基斯坦Bt棉花品种的经济效益
英文文献作者：Nazli, Hina,Sarker, Rakhal,Meilke, Karl D.,Orden, David
英文文献摘要：
Farmers in Pakistan have been growing cotton that contains the first generation of Bt gene since 2002. The cultivation of these varieties, although formally unapproved and unregulated, increased rapidly after 2005. In 2007, nearly 60 percent of the cotton area was under BT varieties. This paper examines the economic performance of Bt cotton in Pakistan based on data collected through a structured questionnaire survey in January-February 2009 in two districts (Bahawalpur and Mirpur Khas). The extent of the impact of Bt cotton on costs of production and yield gains are different across the two districts with their diverse agro-climatic conditions and pest pressures. Seed expenditures increase in both districts, but a decline in the number of bollworm sprays and hence in the expenditure for pesticides is observed and total pesticide control costs (for bollworms and non bollworm pests) declines in both districts. Total production costs decline in Bahawalpur but rise in Mirpur Khas. The yield increases are higher in Mirpur Khas as well, resulting in total revenue and gross margins improving more than in Bahawalpur. The results are similar to other studies of Bt cotton in India and suggest gains for Pakistan from progressing to a regulated national market for Bt cotton technologies.

自2002年以来，巴基斯坦农民一直在种植含有第一代Bt基因的棉花。这些品种的种植，虽然没有正式批准和管制，但在2005年之后迅速增加。2007年，近60%的棉花种植在BT品种下。本文基于2009年1月至2月在两个地区(巴哈瓦尔普尔和米尔普尔卡斯)通过结构化问卷调查收集的数据，调查了巴基斯坦Bt棉花的经济绩效。由于不同的农业气候条件和虫害压力，Bt棉花对生产成本和产量收益的影响程度不同。两个地区的种籽支出都有所增加，但棉铃虫喷洒次数减少，因此农药支出也有所减少，两地区的农药控制总成本(棉铃虫和非棉铃虫害虫)都有所下降。Bahawalpur的总生产成本下降，但Mirpur Khas上升。米尔普尔卡哈斯的产量增加也更高，导致总收入和毛利率比巴哈瓦尔普尔提高更多。这些结果与在印度进行的其他Bt棉花研究相似，并建议巴基斯坦从发展成为一个受监管的Bt棉花全国市场中获益。