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Centre Defends Environmental Release of GM Mustard Hybrid DMH-11 and its Parental Lines in Supreme Court

Mustard blossom. Photo by Vivian Fernandes

Excerpts from the government’s reply of  9 November, 2022 to writ petitions No 260 of 2005 and 115 of 2004 filed by Aruna Rodrigues and others, and Gene Campaign respectively against the Union of India, seeking prohibition on commercial release of genetically-modified mustard hybrid DMH-11. 

The issues raised by the petitioners fall within the domain of the executive aided by scientific and other technical experts. The research, development and use of genetic engineering technologies is a highly technical matter guided by views that emerge from scientific consensus among subject experts. As such, it is most humbly submitted that the inquiry of this Hon’ble Court may be limited to whether there is an adequate regulatory mechanism in place governing this field and whether there has been material compliance with the same.

The controversy raised by the petitioners concerns a conditional approval made to the CGMCP (Centre for Genetic Manipulation of Crop Plants) for environmental release of transgenic mustard hybrid DMH-11 and its parental lines bn 3.6 and modbs 2.99 containing barnase, barstar and bar genes prior to commercial release. This conditional approval has been made after a long and exhaustive regulatory review process which commenced as far back as 2010. It is to be noted that this approval of environmental release prior to commercial release is for the purpose of undertaking seed production and testing of hybrid DMH-11 and developing new parental lines and hybrids under the supervision of Indian Council of Agricultural Research (ICAR).  As such, this conditional approval pertains to an environmental release prior to commercial release and is subject to regulatory and technical oversight as explained later in the affidavit.

At the outset, it is submitted that the Union of India is committed to increasing farm productivity and the income of farmers through development of low-input, high-output agriculture and making the country self-sufficient in edible oil and grain legumes. To achieve this objective, several nations around the world have safely employed genetic engineering (GE) technologies. To safely encourage this endeavour in India, an elaborate statutory scheme exists to ensure effective regulatory review for the research, development and commercial use of GE technologies.

Approximately 55-60 percent of edible oil in India is imported. Strengthening of plant breeding programmes including use of new genetic technologies such as GE technology is critical for meeting emerging challenges in Indian agriculture and ensuring food security while reducing foreign dependency.

Role of GE in Hybrid Mustard Seed Production

The mustard flower contains both male and female parts and predominately self-pollinates or fertilises itself. For producing hybrid seed in mustard, one of the parents (Parent 1) has to be made male sterile (MS), so that it can receive pollen from the other parent (Parent 2). All the seeds collected from Parent 1 will be hybrid seeds and provided to the farmers. Hybrid seed production therefore requires good parents and a pollination control system. A robust pollination control mechanism is required to disallow self-pollination and facilitate cross-pollination to produce hybrid seeds between two different parental lines.

The GE-based hybrid seed production system deployed in mustard by CGMCP involves use of three transgenes, namely, barnase gene that confers male sterility trait is introduced into one of the parental lines. barstar gene that confers restoration of male fertility (MF) trait is introduced in the other parental line, and bar gene that confers resistance to the herbicide glufosinate ammonium (commercial name Basta) is essentially used as a marker gene, to select the barnase (MS) and barstar (MF) containing lines by genetic transformation and is also essential for hybrid seed production.

The male sterile line Varuna bn 3.6 contains bar and barstar genes in a linked fashion allowing the two genes to be inherited together. The barnase gene is expressed only in the tapetum tissue which nourishes the developing pollen by using tapetum specific promoter and hence the resultant plant is male sterile. The fertility restorer line EH-2 modbs 2.99 contains the bar and barstar genes in a linked manner. The bar gene which exists in both parental lines, confers herbicide tolerance to the crop and is useful solely at an intermediate stage.

Since Varuna bn 3.6 is male sterile, it cannot self-pollinate to reproduce. Therefore, the Varuna bn 3.6 MS line is maintained (multiplied) by crossing it with normal Varuna and the progeny of this cross segregates into 50 percent male sterile (containing bar and barnase genes) and the other 50 percent fertile plants without the bar and barnase genes. Separately, EH2 (Early Hira 2) modbs 2.99 line is multiplied by self-pollination since it is not male sterile.

The seed of the hybrid mustard, i.e., hybrid DMH-11 is produced by crossing the male sterile parental line Varuna bn 3.6 (with bar and barnase genes) with restorer parental line, EH modbs 2.99 (with bar and barstar genes). For the production of the hybrid seed, the production plot will be sown with two types of seeds – (1) that obtained from Varuna bn 3.6 x Varuna which will segregate 50:50 into male sterile (containing bar and barnase) and male fertile (no bar and barnase) alternating with EH2 modbs 2.99 plants. Post emergence, Basta will be sprayed on the hybrid seed production plot to eliminate fertile plants that (contain no transgene) from the Varuna bn 3.6 x Varuna cross progeny. The remaining plants will be Varuna bn 3.6 male sterile plants since the bar genes confer herbicide tolerance to the male sterile progeny. These male sterile plants will cross with EH2 modbs 2.99 plants to provide hybrid seed of DMH-11 with very high purity. These seeds will give fully fertile plants in farmers’ fields. The use of the herbicide is to eliminate fertile plants in the hybrid seed production plots and is an essential step for hybrid seed production with the barnase-barstar system.

It is critical to note that it is only the use of barnase and barstar genes that confer fertility to the resulting DMH-11 hybrid. The utility of the bar gene is only at the selection event, to multiply the male sterile parent line.

It is submitted that the development of male sterility line bn 3.6 and restorer line modbs 2.99 in mustard constitutes a complete and functional male-sterilty/restorer system that could be diversified into better combiners and used to produce new hybrids with higher yields in future. In essence, this technology is the beginning of a promising field of research in agriculture which will increase crop yields and farmer income.

Submission Regarding Herbicide Tolerance

At this stage, it is important to appreciate the herbicide tolerance aspect of DMH-11. The following submissions are made in this regard: the GM mustard technology is for hybrid seed production. Hybrids give higher yields in comparison to traditionally bred varieties. GM mustard has not been developed as an herbicide tolerant technology. The HT characteristic/trait present in the GM mustard hybrid seed is essential for eliminating fertile plants in the hybrid seed production plots so that male sterile parent can cross with fertility restorer plant  to provide hybrid seeds.

The petitioners have contended that DMH-11 is HT DMH-11 , which is not appropriate. The term would be appropriate only when the herbicide tolerance (HT) trait in the hybrid is the commercial trait, that is, this trait is the sole reason behind permitting GM mustard from the environmental angle. In the instant case, HT trait is a selection marker for experimental use during development phase of the event followed by limited use of the herbicide in seed production phase under genetic isolation from other mustard varieties.

In India the use of herbicides is regulated by the Central Insecticides Board & Registration Committee (CIB&RC) under Department of Agriculture and Farmers Welfare. Glufosinate and other herbicides are used worldwide including in India on plantation crops based on the approval of CIB&RC.

The use of herbicide by farmers is not permitted in the fields for cultivation of GM mustard crop in accordance with the recommendation made by the Genetic Engineering Appraisal Committee (GEAC), which is the statutory body tasked with such decisions. This is clearly enshrined in conditions VI and VII of the permit letter issued by the Government of India on 25.10.2022. Any such use in the farmers’ field without due approval from CIB&RC would attract appropriate legal action under the Central Insecticides Act, 1968 and Rules, 1971, and The Environment Protection  Act 1986 and Rules made thereunder.

(Photo is of a mustard flower, by Vivian Fernandes)

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