Yields in rice for a long time have stagnated. Though there has been an incremental increase here and there, yields, say for example, in the popular variety, Samba Mahsuri (BPT5204) hover around 5-6 tonnes a hectare.
Scientists at the Indian Institute of Rice Research (IIRR), an Indian Council of Agricultural Research institute, have used a modern tool called genome editing to increase the yields by up to 30-35 per cent.
“The new breeding technique, which is generating a lot of interest across the world, lets scientists to carry out targeted changes to genomes, to get the best possible features, to improve a wide range of traits in various crops,” R M Sundaram, Director of IIRR, told businessline.
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A team of scientists has successfully completed two seasons of testing of the edited rice variety at the biosafety screen house. They used a genome editing technology called CRISPR/Cas (Clustered Regularly Interspaced Short Palindromic Repeats) to edit and mutate the negative regulator.
“It has been a great challenge for researchers to enhance the yield potential of Samba Mahsuri, which is highly popular for the grain quality, while retaining the original grain and cooking qualities,” he said.
“We have edited a negative regulator that limits the number of grains per panicle. As a result, the number of grains per panicle showed an increase of 35 per cent,” Satendra Kumar Mangrauthia, a Senior Scientist at IIRR that headed the research team, said.
Usually, a Samba Masuri plant gives 200-250 grains per panicle, while the genome-edited plant gives over 450 grains per panicle. “This is going to significantly increase the yields,” he said.
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Rise in farmers’ income
This, however, requires IP clearances and permissions for field evaluations before going for elaborate trials and commercial releases.
Satendra Kumar said because of the swiftness involved, the process can help accelerate the delivery of improved varieties.
Satendra said the method could significantly improve the incomes of farmers and ensure food and nutritional security.
Going forward, this technology can also be used to develop varieties that require paddy plants to use less water, fertilisers, and pesticides.
Satendra Kumar and his team started working on genome editing in 2016. They received funding from ICAR- National Agricultural Science Fund (NASF) in 2018 to carry out the genome editing work .
“After establishing initial protocols and standardisation of techniques, the IIRR team developed high yielding version of Samba Mahsuri in two years,” he said.
“We have seen a 35 per cent increase in grain yield while retaining its original grain characteristics. Besides, the edited lines showed strong culm strength that helps in lodging resistance,” he said.
The transgene free homozygous edited lines are ready for field testing and commercialisation.
He felt that it would be desirable to develop some mechanism to acquire licensing for using the technology for the benefit of farmers and society.
Researchers at IIRR informed that there are several such negative regulators present in rice genome that can be targeted for genome editing to improve yield, disease resistance, insect resistance, and abiotic stresses.
The Centre, in its Office Memorandum of March 30, 2022, expedited genome editing by exempting plants falling under the categories of (Site-Directed Nuclease) SDN1 and SDN2 from certain provisions of the Environmental Protection Act Rules, 1989, which governs the regulatory and biosafety of genetically modified organisms (GMOs).
This has helped SDN1 and SDN2 genome-edited plants from not being regulated as GMOs. The development is expected to result in accelerated development of crop varieties with different improved traits, particularly to impart resistance to devastating plant diseases and fight climate change and malnutrition.
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