GM crops

1. Scientific basis and development of GM crops

Modern biotechnology enables targeted alteration of crop genomes through genetic engineering. Conventional breeding recombines existing genetic variation, usually through crosses between compatible plants. Genetic engineering can introduce selected DNA sequences without the same reproductive barriers. A transgenic plant contains introduced genetic material from a non-crossable source; cisgenic approaches use genes from the same species or a sexually compatible species. Not every genome-edited plant contains foreign DNA.

A typical transformation programme identifies a useful gene, joins it to regulatory sequences such as a promoter, and transfers the construct into plant cells. Agrobacterium-mediated transformation uses the natural DNA-transfer capacity of a soil bacterium. Particle bombardment delivers DNA-coated microscopic particles into cells. Transformed cells are selected, regenerated through tissue culture and examined for stable inheritance and expression of the desired trait.

A transformation event is a specific insertion of genetic material into a plant genome. Different events involving the same gene can differ in insertion site, copy number and expression. Biosafety assessment therefore evaluates the particular event and its intended use, rather than treating every GM crop as equivalent. Stacked crops combine two or more engineered traits or events.

• Common objectives include insect resistance, herbicide tolerance, disease resistance, nutritional improvement and tolerance to environmental stresses.
• Genetic engineering can protect yield by reducing losses; it does not automatically increase a crop’s intrinsic yield potential.

2. Major traits and representative crops

Bt crops express insecticidal proteins derived from Bacillus thuringiensis, a soil bacterium. In susceptible insects, certain Bt proteins are activated in the gut, bind to appropriate receptors and disrupt gut cells. Their specificity depends on the protein and the insect. Bt cotton was developed principally against bollworms; it does not control all pests, including many sucking insects.

Bollgard I cotton expresses Cry1Ac, whereas Bollgard II expresses Cry1Ac and Cry2Ab. Combining toxins with different modes of interaction can delay resistance, but does not make resistance impossible. Refuges of non-Bt plants support susceptible insects that can mate with resistant survivors. Compliance with refuge requirements, pest surveillance and integrated pest management remain important.

Herbicide-tolerant crops survive applications of particular herbicides, permitting weed control without killing the crop. This trait differs from insect resistance. Repeated reliance on a single herbicide can select resistant weeds, while gene flow may transfer tolerance to compatible relatives. Herbicide-tolerant Bt cotton has not been approved for commercial cultivation in India.

Golden Rice has been engineered to produce beta-carotene, a precursor of vitamin A, in the edible endosperm. Its purpose is nutritional improvement, not insect control. India’s mustard hybrid DMH-11 uses the barnase-barstar system to facilitate hybrid seed production: barnase induces male sterility, while barstar restores fertility. The construct also includes the bar gene, associated with glufosinate tolerance and selection; this does not itself constitute approval for agricultural herbicide use.

• Bt brinjal targets the fruit and shoot borer; India placed its commercial release under moratorium in 2010.
• Trait, crop species, transformation event and receiving environment must all be identified when judging a GM product.

3. Benefits, risks and biosafety assessment

Potential benefits include reduced losses from target pests, lower use of some insecticides, improved crop quality and more predictable production. Outcomes depend on pest pressure, seed cost, irrigation, agronomy and farmer practices. Reduced spraying against bollworms does not necessarily imply lower use of every pesticide, especially if secondary pests become important.

Environmental assessment examines gene flow, effects on non-target organisms, persistence, weediness and the evolution of resistant pests or weeds. Gene flow is possible only where biological compatibility and opportunities for pollination exist; it is not an automatic transfer to every neighbouring plant. Biodiversity effects also depend on how a crop changes cultivation practices.

Food and feed assessment considers molecular characterisation, composition, toxicity, allergenicity and nutritional effects. Comparison with an appropriate conventional counterpart helps identify meaningful differences, but is not by itself proof of safety. A finding about one assessed event should not be generalised into either universal safety or universal danger for all GM crops.

Socioeconomic concerns include seed affordability, intellectual property, access to suitable varieties, liability, market acceptance and farmers’ capacity to follow stewardship requirements. These issues are related to, but distinct from, biological safety. Transparent assessment, independent research, traceability where required and post-release monitoring can strengthen public confidence.

• Integrated pest management combines resistant varieties with monitoring, biological control and judicious chemical use.
• The precautionary approach calls for proportionate safeguards under uncertainty, not a presumption that all biotechnology products have identical risks.

4. India’s regulatory framework and international context

The Rules, 1989 under the Environment (Protection) Act, 1986 govern hazardous microorganisms and genetically engineered organisms or cells. Institutional Biosafety Committees oversee relevant work within institutions. The Review Committee on Genetic Manipulation, under the Department of Biotechnology, monitors safety aspects of ongoing research and specified research activities.

The Genetic Engineering Appraisal Committee appraises activities involving large-scale use of hazardous microorganisms and recombinants from the environmental angle, and proposals for release of genetically engineered organisms into the environment, including experimental field trials. State Biotechnology Coordination Committees and District Level Committees have monitoring and enforcement roles. Food regulation also involves the Food Safety and Standards Authority of India under the Food Safety and Standards Act, 2006.

Bt cotton’s commercial approval in 2002 was a major regulatory milestone. Bt brinjal’s proposed commercial release was placed under moratorium in 2010. In October 2022, conditional environmental release of DMH-11 mustard and its parental lines was allowed for seed production and testing under applicable guidelines. This should not be described as unrestricted farmer-level commercial cultivation. In July 2024, a Supreme Court bench delivered a split verdict on the approval challenge, requiring consideration by a larger bench.

India is a Party to the Cartagena Protocol on Biosafety, which addresses the safe handling, transport and use of living modified organisms, especially transboundary movement. A living modified organism must be capable of transferring or replicating genetic material; highly processed products such as refined oil are therefore conceptually different from viable GM seeds.

• GEAC means Genetic Engineering Appraisal Committee, not Genetic Engineering Approval Committee.
• Research permission, import permission and cultivation approval are not interchangeable.

5. Genome editing and examination distinctions

Genome editing tools such as CRISPR-Cas can make targeted DNA changes. SDN-1 generally involves repair of a targeted break without a supplied repair template; SDN-2 uses a template for a defined small alteration; SDN-3 introduces larger DNA sequences. In March 2022, India exempted SDN-1 and SDN-2 genome-edited plants free from exogenous introduced DNA from Rules 7–11 of the Rules, 1989, subject to the prescribed framework. This is not a blanket exemption for all edited organisms.

For Prelims, separate the technique from the trait. Herbicide tolerance may arise through different breeding methods, and a GM crop need not be herbicide-tolerant. Similarly, hybrid seeds are not necessarily GM, and GM plants are not necessarily sterile. Evaluate scientific claims separately from the legal status of a crop in a particular country.

• Transgenic does not mean hybrid; genome-edited does not necessarily mean transgenic.
• Approval abroad does not confer approval in India.

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