The recent approval of GM Mustard by the Ministry of Environment, Forests and Climate Change (MoEF&CC), Government of India for the environmental release of genetically modified (GM) mustard hybrid for cultivation is indeed a landmark decision breaking a long logjam on the release of GM food crops.
The National Academy of Agricultural Sciences (NAAS) and the Trust for Advancement of Agricultural Sciences (TAAS) welcome this as a highly progressive step towards an Atmanirbhar Bharat. The GM technology for hybrid seed production developed by the University of Delhi will play an important role in reducing the edible oil import burden and in moving towards self-sufficiency in edible oil production.
The decision to release GM mustard will encourage more research and innovations to reduce the environmental footprints of agriculture, develop climate-resilient crops, and thereby assure food and nutritional security of the country.
Mustard (Brassica juncea) is an important oilseed crop of India, grown in around 6-7 million ha area during the rabi season mostly in the states of Rajasthan, Haryana, Punjab, and Madhya Pradesh. Currently, India has a deficit of edible oils by almost 55-60 percent of the total consumption.
In the financial year 2020-21, around 13.35 million tonnes of edible oils were imported at a total cost of around Rs 117,000 crores in foreign exchange. India desperately requires an increase in the productivity of oilseed crops grown in the country.
The average mustard yield in India is 1.0-1.3 tonnes/hectare. This is stagnant for almost two decades. Globally, yields of rapeseed have considerably increased with the introduction of hybrids. More than 90% of the rapeseed crop in Canada, grown in around 8.7 million ha, is under hybrids. Most of the rapeseed grown in China and Europe is also hybrids.
Mustard is predominantly a self-pollinating crop with flowers having both male and female parts. A robust pollination control system is required that would facilitate cross-pollination to help develop hybrids between any two selected diverse parental lines. Such a system has been developed by the Centre for Genetic Manipulation in Crop Plants, the University of Delhi, which used three transgenes – barnase, barstar, and bar (the bar gene confers resistance to herbicide Basta and is needed for selecting the transformed lines).
The Barnase gene is specifically expressed in the tapetum cells using a tapetum specific gene promoter TA29. The tapetum provides nutrients to the developing pollen. The Barnase gene product is an RNase enzyme, which kills the tapetum resulting in pollen degeneration leading to male sterility. This causes male sterility in the resultant transgenic plant.
Such transgenic parental line (Event Var bn 3.6) is then used as a female parent and fertilized by another parent (Event EH-2 modbs2.99 harbouring the Barstar gene) to develop the hybrid. Barstarcompletely negates the effect of the Barnase protein; as a consequence, the hybrid seed between the two lines is fully fertile and the farmers can reap the benefit of higher yield from the hybrid.
The first hybrid developed using the GE pollination control mechanism is DMH-11. The trials conducted over three years at eight locations under the supervision of ICAR-DRMR, Bharatpurshowed DMH-11 to have, on average, a yield advantage of 28% over the mega variety Varuna and 37% over the zonal checks. With the availability of a robust pollination control system in mustard, the way is clear for developing even higher-yielding and canola-quality hybrids.
Thus, hybrid DMH-11 could safely be grown in the farmers’ fields. Now that GM mustard has been given environmental clearance, urgent efforts are needed to test DMH-11 hybrid at different locations in the mustard belt by ICAR and State Agricultural Universities (SAUs).
This is done in this growing season by ICAR-DRMR and the Department of Agriculture, MOA&FR. Using the available seed, around 100 demonstrations could easily be conducted in the current rabi season, and efforts are needed to produce more hybrid seeds through public-private partnerships so that a larger area could be covered in the next cropping season.
Also, the scientists are encouraged to accelerate breeding efforts to produce new high-yielding disease and pest-resistant hybrids using this new technology cleared by the Government of India.
It is an interesting coincidence that Australia has recently on 19 October, released herbicide-tolerant GM Indian mustard to meet the increasing global demand of edible oil.