Prospects for Bt Cotton Technology in India
R.B. Barwale, V.R. Gadwal, Usha Zehr, and Brent Zehr
Maharashtra Hybrid Seed Company, India
Cotton is a very important crop in India; farmers there face the challenge of losses due to various insect pests. The first genetically modified crop in India, Bt cotton, has been introduced to address bollworm infestation. The process of introduction of Bt cotton took six years of experimentation, during which time agronomic, environmental, and biosafety data was generated and reported. The trials conducted prior to commercialization clearly established the superior performance of Bt cotton, as demonstrated by increased yields and reduction in application of pesticides. Transgenic technology is suitable for the Indian farmer despite small farm holdings. The area under Bt cotton is projected to increase rapidly in the coming years.
Key words: Bt, Bt cotton, transgenic crops.Introduction
Cotton provides a livelihood to more than 60 million people in India by way of support in agriculture, processing, and use of cotton in textiles. Cotton contributes 29.8% of the Indian agricultural gross domestic product, and nearly nine million hectares of land in India is used to produce 14.2 million bales of cotton lint.
Indian cotton production is third in the world in quantity, although the productivity is substantially low. The major reason for this low productivity is damage caused by insect pests—notably Helicoverpa armigera, commonly referred to as American Bollworm. Nearly Rs.12 billion worth of pesticides are used in India to control just the bollworm complex of cotton. Mahyco (Maharashtra Hybrid Seed Company), in collaboration with Monsanto, has introduced Bt cotton technology into India. Bt cotton carries the Cry1Ac gene derived from the common soil bacterium Bacillus thuringiensis var. kurstaki, which results in the expression of the Cry1Ac protein that confers resistance to the bollworm complex.
Experience in Other Parts of the World
Bt cotton has already been commercialized in six countries: the United States (1996), Australia (1997), South Africa (1997), Argentina (1998), Mexico (1996), China (1998), and Indonesia (2000). Bt cotton is being extensively field tested under permit in Brazil, Colombia, Thailand, and Zambia. Globally, Bt cotton was planted on one million acres (405, 000 ha) in 2000. Due to its excellent performance, the benefits to the farmer of Bt cotton have been consistently superior for the six years of commercialization.
Bt Cotton in India
Bt cotton seeds were first tested in India for germination, vigor, and insect efficacy. Other experiments were conducted to confirm the environmental safety of Bt cotton, including tests of gene flow, persistence of the transformed plants, weediness characteristics, crossability of the transgenic pollen with the nontransgenic relative and near relatives, effect of the pollen on insects and nontarget organisms, and changes in the soil microbial flora (Table 1). These studies were conducted under the unique environmental conditions of India and with the Bt trait in Indian germplasm. Studies of the molecular characterization and stability of the Cry1Ac gene were also carried out, as well as feeding studies and tests of food and feed safety, toxicity, and allergenicity.
Table 1. Timeline summary for regulatory processes leading to commercial release of Bt cotton in India.
Bt Cotton—Agronomic Benefits
Trials conducted in several locations in 1998/99, 1999/2000, 2000/01, and 2001/02 demonstrated the following agronomic benefits of Bt cotton:
Bt Cotton—Approval for Commercial Cultivation
The Genetic Engineering Approval Committee (GEAC), in its 32nd meeting, held on March 26, 2002, made the landmark decision of approving cultivation of Bt cotton in India; three hybrids (MECH 162 Bt, MECH 184 Bt, and MECH 12 Bt) were approved for cultivation with the stipulation that certain conditions be met (Figure 1; Table 2). These hybrids are high yielding and produce medium-long- to long-staple fiber.
The GEAC also approved production of seed; subsequently, seed for cultivating 100,000 acres (40,485 ha) was available for planting by Indian farmers. The seed was distributed in the states of Maharashtra, Madhya Pradesh, Karnataka, Andhra Pradesh, Gujarat, and Tamil Nadu in the kharif 20021 planting season. The areas planted to Bt cotton were 14746, 2220, 3908, 5608, 8854, and 2702 hectares spread over the three hybrids.
Figure 1. Comparison of a Bt cotton hybrid (right) with its non-Bt hybrid counterpart (left) at first picking stage during a regulatory field trial in India. Three intra-hirsutum Bt cotton hybrids were approved for commercialization by the government of India in 2002.
Table 2. Commercial cultivation of Bt cotton hybrids in India, 2002 (hectares).
This year's cotton-growing season in India was affected by high rainfall in some areas and a long dry spell followed by heavy downpours (resulting in unfavorable conditions for cotton cultivation) in other areas. The overall pest pressure this year for bollworm complex was also low. However, across the cotton-growing areas, control of the bollworm complex was observed in Bt cotton; the amount of spraying required, if any, was significantly lower for Bt than for non-Bt cotton hybrids. Bt cotton yields were significantly higher than those of non-Bt cotton, and the average increase in yield was about 30% over non-Bt hybrids in similar conditions. The quality of Bt cotton was cleaner with better color, and Bt cotton provided rates commensurate with the quality of the fiber based on the hybrids available.
The data in Table 3 shows that in addition to the substantial increase in yield, there is a significant decrease in the number of insecticide sprays associated with the use of Bt cotton—the overall average indicates a yield increase of 8.1 quintals2 of cotton and a reduction of 1.93 sprays. These two factors add to the total economic benefit. Table 3 indicates that there is an average additional income of more than Rs.18,000/ha for Bt compared to non-Bt cotton.
Table 3. Bt cotton results from kharifa 2002 season, June-December (yield in quintalsb).
Projection of Bt Cotton for Next Three Years
Today, Bt cotton comprises 0.78% of the hybrid cotton area (Table 4). It is projected that the 2003/04 and 2004/05 seasons will have Bt coverage of 6.40% and 11.65%, respectively.
Table 4. Projection of Bt cotton planting area in India (hectares).
The benefits of Bt cotton in India are in line with those enjoyed by farmers worldwide who have cultivated Bt cotton. The area under Bt cotton cultivation is expected to increase—it is likely that an area of 500,000 hectares will be covered by 2005, leading to increased production and reduced costs in an environmentally favorable manner. This will positively affect the livelihood of millions of small farmers by improving their net incomes.
Bt cotton is undoubtedly the most extensively studied cotton variety today. Rigorous scientific studies conducted in India and abroad demonstrate that Bt cotton and its products are safe for the environment, humans, animals, and agriculture. In fact, the use of Bt cotton is a positive step towards environmental protection because it makes possible the reduction of the insecticide load in the environment and reduces handling of such chemicals by farmers. This reduced use of insecticides will enhance the effectiveness of biological controls and implementation of Integrated Pest Management (IPM) programs. The higher farm income observed in the experiments has now been demonstrated by the large-scale use of Bt cotton by Indian farmers, and the incorporation of the gene is proving an effective and environmentally friendly plant protection tool resulting in greater cultivation of Bt cotton in the coming years. The cotton trade is looking forward to the productivity and quality benefits of Bt cottonseed. Efforts are being made to incorporate another gene (Bollgard II) to improve efficacy and postpone possible resistance problems. As newer products are approved in the regulatory system, it is likely that farmers will have greater choice to plant hybrids according to market quality requirements.
1 Kharif refers to a crop that is harvested at the beginning of winter.
2 1 quintal = 100 kg.
Suggested citation: Barwale, R.B., Gadwal, V.R., Zehr, U., & Zehr, B. (2004). Prospects for Bt cotton technology in India. AgBioForum, 7(1&2), 23-26. Available on the World Wide Web: http://www.agbioforum.org.
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