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CONCEPT – GENETICALLY MODIFIED (G.M.) CROPS
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- Brinjal or eggplant (Solonum melongena) is the major vegetable crop in India and is vulnerable to many diseases caused by insects, pests, fungi, bacteria and viruses. Brinjal production is extensively affected by the brinjal fruit and shoot borer (FSB, Leucinodes orbonalis). Use of conventional chemical pesticides not only damages the environment, including the biotic and abiotic components, but also affects human health.
- Bt Brinal was developed to combat brinjal fruit and shoot borer that has an advantage, minimizing the use of chemical pesticides. Extensive biosafety investigations, nutritional studies, substantial equivalence studies, relative toxicity and allergenicity assessment using animal models like Sprague Dawley rats, Brown Norway rats, rabbit, fish, chicken, goats, etc. revealed no significant differences between genetically modified brinjal and its native counterpart. Bt brinjal effectively controlled the target pest and was found to be safe for environment and human health. In spite of all the scientific studies, release of Bt Brinjal including its production, use of Bt toxin, use of chemical pesticides in controlling the FSB in native brinjal, along with the perspective of public opinion and government initiatives.
- Bt Brinjal - India's first vegetable biotech crop (first GM food crop) : The Bt brinjal variety was developed using a transformation process similar to the one used in the development of Bt cotton, a widely used biotech crop in India.
- Developed by the Maharashtra-based seed company, Mahyco, Bt brinjal was the first food crop made to contain an insecticidal protein, called cry1 ac, sourced from the genes of the soil bacterium, Bacillus thuringienesis.
- The Genetic Engineering Approval Committee (GEAC), in its 97th meeting held on 14th Oct 2009, recommended the commercial release of Bt Brinjal Event EE-1 developed indigenously by Mahyco in collaboration with the University of Agricultural Sciences (UAS), Dharwad and the Tamil Nadu Agricultural University (TNAU), Coimbatore. This was a penultimate step to commercialize Bt brinjal hybrids and varieties in the country (MOEF, 2009).
- Though this was cleared for commercial cultivation it was put in deep-freeze, by former Union Environment Minister Jairam Ramesh in 2010 on the grounds that there was scientific and public disagreement on its safety. It remained banned.
- How it works : Bt brinjal incorporates the cry1Ac gene expressing insecticidal protein to confer resistance against FSB. The cry1Ac gene is sourced from the soil bacterium Bacillus thuringiensis (Bt). When ingested by the FSB larvae, the Bt protein is activated in the insect's alkaline gut and binds to the gut wall, which breaks down, allowing the Bt spores to invade the insect's body cavity. The FSB larvae die a few days later.
- Who developed : Bt Brinjal was developed by the Maharashtra Hybrid Seeds Company (Mahyco). It used a DNA construct containing the cry1Ac gene, a CaMV 35S promoter and the selectable marker genes nptII and aad, to transform young cotyledons of brinjal plants. A single copy elite event, named EE-1, was selected and introduced into hybrid brinjal in Mahyco's breeding program.
- Mahyco also donated the Bt brinjal technology to the Tamil Nadu Agricultural University (TNAU), Coimbatore and University of Agricultural Sciences (UAS), Dharwad. The event EE-1 was backcrossed into open-pollinated brinjal varieties. Mahyco also donated the technology to public research institutions in the Philippines and Bangladesh.
- The National Center on Plant Biotechnology (NRCPB) developed Bt brinjal varieties expressing the cryFa1 gene. The technology was subsequently transferred to firms like Bejo Sheetal, Vibha Seeds, Nath Seeds and Krishidhan Seeds. The Indian Institute of Horticultural Research (IIHR) also developed Bt brinjal using the cry1Ab gene. Scientists are also looking for ways to develop Bt brinjal in conjunction with other multiple and beneficial traits.
- Regulatory approval : Bt brinjal is the first food crop under evaluation for commercial release in India. Since its development in 2000, the crop has undergone rigorous scientific evaluation to assess its food safety, environmental safety, human and animal health safety and biodiversity. Given below is the regulatory process followed -
- Rigorous scientific tests, including toxicity and allergenicity evaluation as well as nutritional studies on rabbits, rats, carps, goats, broiler chickens and dairy cows, confirmed that Bt brinjal is as safe as its non-Bt counterparts. The safety of Bt brinjal was further validated by the results of the studies on pollen escape, effects on soil microflora and non-target organisms, agronomy, invasiveness and Bt protein degradation. Results of the studies demonstrated that Bt brinjal does not affect beneficial insects such as aphids, leafhoppers, spiders and lady beetles.
- Benefits of Bt Brinjal : Bt brinjal was found to be effective against FSB, with 98% insect mortality in Bt brinjal shoots and 100% in fruits compared to less than 30% mortality in non-Bt counterparts. It needs 77% less insecticides than non-Bt counterparts for control of FSB, and 42% less for the control of all insect pests of brinjal. The benefits of Bt brinjal, translate to an average increase of 116% in marketable fruits over conventional hybrids, and 166% increase over popular open-pollinated varieties (OPVs). Furthermore, the significant decrease in insecticide usage reduced the farmers' exposure to insecticides and results in a substantial decline in pesticide residues in brinjal fruits.
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