Search

This essay engages the problem of agriculture and the market from the point of view of production. India is a nation of small-holder farmers where agriculturalists have been integrated into commercial cash cropping over long-distance commodity chains for a very long time. It is the nature of those markets, their relation to the state, and to the farming household that undertakes agricultural commodity production, that has changed. Through a techno-political history of the cotton seed, I examine new conjunctions between the cultivating household and the market to illustrate the paradox of small-holder commercial agriculture in India. [ABSTRACT FROM AUTHOR]

The present study was planned to explore the relationship between soil chemistry with bacterial population of Bt and non-Bt cotton and their phenotypic and molecular characteristics. The pre-plant soil and rhizospheres of Bt and non-Bt cotton were collected and analyzed for some soil parameters and bacterial population. The bacterial isolates were analyzed for their morphological, biochemical, and molecular characteristics. Bacterial population showed a significant (p < 0.05) positive correlation with clay content, electrical conductivity, organic matter, total nitrogen, and available phosphorus and potassium negative with correlation with pH. Bt cotton showed a non-significant effect on the soil parameters, significant decrease in bacterial population, change in the morphological and biochemical characteristics of rhizobacteria and replacement of four bacterial species with five new ones suggests the potential effect of Bt cotton on its rhizoflora. The rhizosphere of non-Bt cotton cultivated in the fertile agriculture field was found to be the best for bacterial growth. [ABSTRACT FROM AUTHOR]

Growing areas under transgenic crops have created a concern over their possible adverse impact on the soil ecosystem. This study evaluated the effect of Bt-cotton based cropping systems on soil microbial and biochemical activities and their functional relationships with active soil carbon pools in Vertisols of central India (Nagpur, Maharastra, during 2012-2013). Culturable groups of soil microflora, enzymatic activities and active pools of soil carbon were measured under different Bt-cotton based cropping systems (e.g. cotton-soybean, cotton-redgram, cotton-wheat, cotton-vegetables and cotton-fallow). Significantly higher counts of soil heterotrophs (5.7-7.9 log cfu g−1 soil), aerobic N-fixer (3.9-5.4 log cfu g−1 soil) and P-solubilizer (2.5−3.0 log cfu g−1 soil) were recorded in Bt-cotton soils. Similarly, soil enzymatic activities, viz. dehydrogenase (16.6-22.67 µg TPF g−1 h−1), alkaline phosphatase (240-253 µg PNP g−1 h−1) and fluorescein di-acetate hydrolysis (14.6-18.0 µg fluorescein g−1 h−1), were significantly higher under Bt-cotton-soybean system than other Bt- and non-Bt-cotton based systems in all crop growth stages. The growth stage-wise order of soil microbiological activities were: boll development > harvest > vegetative stage. Significant correlations were observed between microbiological activities and active carbon pools in the rhizosphere soil. The findings indicated no adverse effect of Bt-cotton on soil biological properties. [ABSTRACT FROM AUTHOR]

TransgenicBt-cotton producesBt-toxins (Cryproteins) which may accumulate and persist in soil due to their binding ability on soil components. In the present study, the potential impacts ofBt- and non-Btgenotypes of cotton on soil microbial activity, substrate use efficiency, viable microbial population counts, and nutrient dynamics were studied. Two transgenicBt-cotton genotypes (CIM-602 CIM-599) expressingcry1 Acgene and two non-Btcotton genotypes (CIM-573 and CIM-591) were used to evaluate their impact on biological and chemical properties of soil across the four locations in Punjab. Field trials were conducted at four locations (Central Cotton Research Institute-Multan, Naseer Pur, Kot Lal Shah, and Cotton Research Station-Bahawalpur) of different agro-ecological zones of Punjab. Rhizosphere soil samples were collected by following standard procedure from these selected locations. Results reveled thatBt-cotton had no adverse effect on microbial population (viable counts) and enzymatic activity of rhizosphere soil. Bacterial population was more inBt-cotton rhizosphere than that of non-Btcotton rhizosphere at all locations. Phosphatase, dehydrogenase, and oxidative metabolism of rhizosphere soil were more inBt-cotton genotypes compared with non-Btcotton genotypes. Cation exchange capacity, total nitrogen, extractable phosphorous, extractable potassium, active carbon, Fe and Zn contents were higher in rhizosphere ofBt-cotton genotypes compared with non-Btcotton genotypes. It can be concluded from present study that the cultivation ofBt-cotton expressingcry1 Achad apparently no negative effect on metabolic, microbiological activities, and nutrient dynamics of soils. Further work is needed to investigate the potential impacts ofBt-cotton on ecology of soil-dwelling insects and invertebrates before its recommendation for extensive cultivation. [ABSTRACT FROM AUTHOR]

Cotton plants (genusGossypium) are grown on more than 30 million hectares worldwide and are a major source of fiber. The plants possess a wide range of direct and indirect resistance mechanisms against herbivorous arthropods. Direct resistance mechanisms include morphological traits such as trichomes and a range of secondary metabolites. The best known insecticidal compounds are the terpenoid gossypol and its precursors and related compounds. Indirect resistance mechanisms include herbivore-induced volatiles and extrafloral nectaries that allow plants to attract and sustain natural enemy populations. We discuss these resistance traits of cotton, their induction by herbivores, and their impact on herbivores and natural enemies. In addition, we discuss the use of genetically engineered cotton plants to control pest Lepidoptera and the influence of environmental factors on the resistance traits. [ABSTRACT FROM AUTHOR]

China was the first developing country to introduce Bt cotton on a large scale. This paper provides an in-depth economic analysis of Bt cotton production by small-scale farmers in China. Data were collected in 2002 in Linqing County, in Shandong Province and comprised a season-long cotton production monitoring with 150 farmers and complementary household interviews. For quality assessment, the Bt toxin concentration of the various Bt varieties used by the farmers was determined for each plot. All farmers were growing insect resistant Bt cotton varieties. Yet, they sprayed high amounts of chemical insecticides, out of which 40% were extremely or highly hazardous. The paper reviews methodological issues inherent to impact assessment of crop biotechnology and identifies market and institutional failure as possible reasons for continued high pesticide use. Using the damage function methodology the coefficients for both damage control inputs, i.e., Bt varieties (measured as toxin concentration), and insecticide quantity were not significantly different from zero. Results show that absence of enabling institutions and lack of farmer knowledge can considerably limit the benefits of Bt cotton for small-scale farmers. The paper points out the importance to include the institutional conditions in the evaluation of agricultural biotechnology in developing countries. [ABSTRACT FROM AUTHOR]