On GM, follow the science

Source: The post is based on the article “On GM, follow the science” published in The Indian Express on 24th December 2022. 

Syllabus: GS3- Awareness in the field of biotechnology

Relevance: Use of recombinant technology.

News: The article explains the issues related to the environmental release of the GM mustard variety called DMH-11. 

GM is a disruptive technology because it can bring about targeted changes in crop varieties that cannot be achieved through normal breeding of plant lines. 

What is the need for hybrid technology? 

Hybrid plants that result from the crossing of genetically diverse parents generally demonstrate higher yields and wider adaptation. 

Hybrids typically show 20-25% yield increases over conventional varieties. It can play an important role in boosting the yields of rapeseed mustard. India’s current mustard yield is 1.2-1.3 tonnes per hectare. It is roughly half of the global average.  

In 2021-22, India spent Rs 1,56,800 crore on the import of 14.1 mt of edible oils. Hybrid technology can lead to the reduction of import dependence on edible oil. 

What is the role of GM hybrids? 

Hybrid seed production requires an efficient male sterility and fertility-restoration system. The purpose is to ensure that one of the parent lines can be crossed with the pollen from only the other parent, even as the resultant plant is fertile.  

The existing mustard hybrids have limitations of sterility breakdown under certain environmental conditions. It results in lower seed purity.  

The GM “Barnase-Barstar” system provides an alternative route for hybridisation in mustard that is robust and addresses the sterility breakdown problems. This technology has been successfully deployed in other countries. 

DMH-11 uses the “barnase-barstar” system with some improvements to breed the hybrid.  

What are the arguments against the allegations of safety on GM mustard?  

DMH-11 has undergone all the required regulatory testing processes. It was tested in confined field trials at multiple locations. It showed around 28%  higher yield over the national best mustard variety Varuna.  

It has been subjected to all the biosafety tests required under the officially stipulated guidelines and rules. 

The doubters have questioned the safety of the three genes called Barnase, Barstar and Bar that are used to develop GM mustard. Extensive studies on GM mustard lines have established their safety. 

The final allegation levelled against DMH-11 is that it will promote use of herbicides. The Bar gene does confer resistance to the herbicide glufosinate. But the gene has been used as a selectable marker in tissue culture during the breeding process.  

The herbicide-tolerance trait in both the Barnase female and Barstar male lines is to be exploited only for the production of hybrid seed and not in the commercial cultivation of hybrids. The GEAC has also approved herbicide use only for hybrid seed production.  

GM crops are today grown in over 30 countries. Adoption rates of GM traits have been more than 95% in some cases with no evidence of adverse effects.