Monsanto’s Bt-cotton NC 33B, planted in northern China for more than one decade, effectively controls cotton bollworms; however the understanding of its potential effects on soil microorganisms is limited. The dynamics of eubacterial, fungal and actinomycetes population sizes in rhizosphere soil of the Bt cotton were analysed by realtime PCR (qPCR) at the different growth stages under field con...

In the past, scientific research has predicted a decrease in the effectiveness of Bt cotton due to the rise of secondary and other sucking pests. It is suspected that once the primary pest is brought under control, secondary pests have a chance to emerge due to the lower pesticide applications in Bt cotton cultivars. Studies on this phenomenon are scarce. This article furnishes empirical eviden...

Laboratory studies were conducted using ELISA and bioassays (Helicoverpa zea) to investigate temporal Cry protein expression in field-grown single (‘Bollgard’) and dual-toxin (‘Bollgard II’) Bt cotton. In single-toxin Bt cotton, Cry1Ac levels changed significantly as the season progressed, exhibiting ca. 3-fold difference in Cry1Ac expression between the highest date (6.2 ppm—12 June) and the l...

Introduction Pakistan is the 4th top producer of cotton in the world (Table 1), yet in terms of yield it is at the distant 10th position. There are many possible reasons for low cotton yields in Pakistan—high prices of agricultural inputs (pesticides, fertilizers, etc.), higher intensity of insect and pest attacks, deficiency of water for irrigation, lack of advanced technologies and awareness,...

Given that the controversy over success and failure of Bt technology still exists, this paper discusses the available field studies that have addressed agro-economic questions of Bt cotton cultivation in India. Since a meta-analysis of studies can give only partial conclusions, owing to differences across study methodologies and coverage, this paper takes a different strategy, i e, looking not ...

Widespread planting of crops genetically engineered to produce insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) imposes selection on many key agricultural pests to evolve resistance to Bt. Fitness costs can slow the evolution of Bt resistance. We examined effects of entomopathogenic nematodes on fitness costs of Bt resistance in the pink bollworm, Pectinophora gossypiella (Sau...

Field studies were performed during 2005 and 2006 to determine bollworm, Helicoverpa zea (Boddie), and tobacco budworm, Heliothis virescens (F.), larval behavior on conventional non-transgenic cotton plants (Coker 312), and on transgenic Bacillus thuringiensis Berliner (Bt) plants expressing the Vip3A protein or a combination of Vip3A + Cry 1Ab proteins (VipCot). Plants representing each of the...

robust information of genetic diversity among bt cotton genotypes is still lacking and availability of several marker systems has prompted us to compare their utility for the detection of genetic diversity. here, we report the comparative efficiency of morphological and molecular markers (est-ssrs and issrs) in determining the genetic diversity among 30 pakistani bt cotton genotypes. three diff...

Widespread planting of crops genetically engineered to produce insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) imposes selection on many key agricultural pests to evolve resistance to Bt. Fitness costs can slow the evolution of Bt resistance. We examined effects of entomopathogenic nematodes on Þtness costs of Bt resistance in the pink bollworm, Pectinophora gossypiella (Saun...

Transgenic crops producing toxins from the bacterium Bacillus thuringiensis (Bt) kill insect pests and can reduce reliance on insecticide sprays. Although Bt cotton (Gossypium hirsutum L.) and Bt corn (Zea mays L.) covered 26 million ha worldwide in 2005, their success could be cut short by evolution of pest resistance. Monitoring the early phases of pest resistance to Bt crops is crucial, but ...