ICAR on Sunday announced the release of its two new rice varieties, which is the world’s first to be developed through genome editing technology, for which research started as early as in 2018 under the National Agricultural Science Fund Project in two popular varieties Samba Mahsuri (BPT5204) and MTU1010 (Cottondora Sannalu) grown across India in more than 9 million hectares.
Though Samba Mahsuri, a fine-grain rice variety fetches more income to farmers due to higher market price, it has moderate yield potential of 4.5 tonnes/ha, and is highly sensitive to biotic and abiotic stresses as well as vulnerable to climate change. It takes 145-150 days for complete maturity (long duration) and has incomplete panicle emergence.
But the new variety DRR Dhan 100 (KAMALA), developed from Samba Mahsuri using genome editing technology by Hyderabad-based ICAR-Indian Institute of Rice Research, has increased grain number per panicle. Scientists have developed genome edited SDNI mutant of Cytokinin Oxidase 2 (CKX2) gene, also known as Gn 1 a to increase grain number per panicle in Sambha Mahsuri.
This line showed superior yield, drought tolerance, high nitrogen use efficiency and 20 days earliness over its parent BPT 5204. Scientists also have obtained approval of the Biosafety Committee of the IIRR. The approval of the Review Committee on Genetic Manipulation (RCGM) was sought on 31 May 2023 to consider SDNI genome edited lines free of exogenous introduced DNA as equivalent to conventional mutant/breeding line, ICAR said in a statement.
It was tested in the multilocation field trials under All India Coordinated Research Project on Rice (AICRPR) during 2023 and 2024. The genome edited line (IET 32072) showed 19 per cent yield superiority over Samba Mahsuri. Kamala recorded an average yield of 5.37 tonnes/ha, with a potential of 9 tonnes/ha, as seen from its two years of trial in 25 locations as against 4.5 tonnes/ha of parent variety Sambha Mahsuri.
Kamala matures in 130 days (15-20 days earlier than the duration of Samba Mahsuri), which will help help farmers save water and fertilizers, as well as in reducing methane emission. It has strong culm and lodging resistance, suitable for Andhra Pradesh, Telangana, Karnataka, Tamil Nadu, Kerala, Chhattisgarh, Maharashtra, Madhya Pradesh, Odisha, Jharkhand, Bihar, Uttar Pradesh, and West Bengal.
On the other hand, MTU1010 (Cottondora sannalu) is also very popular among the farmers as it has long-slender grain type, having yield potential of 7 tonnes/ha, matures in 125-130 days, suitable as a Rabi season crop in southern region. However, it is sensitive to several abiotic stresses including drought and salinity.
But scientists at New Delhi-based Indian Agricultural Research Institute (IARI), who have developed the Pusa DST Rice 1 from MTU1010 through genome editing, have genome edited SDNI mutant of Drought and Salt Tolerance (DST) gene, and was tested in the multilocation field trials under AICRPR during 2023 and 2024.
Pusa DST Rice 1 exhibits significant average superiority of 9.66 per cent with an average yield of 3508 kg/ha over the parent rice variety, MTU 1010 (3199 kg/ha) under Inland Salinity stress. It also showed superiority of 14.66 per cent over the parent, MTU 1010 under Alkalinity condition with an average yield of 3731 kg/ha over the parent rice variety, MTU 1010 (3254kg/ha) and 30.4 per cent yield advantage with an average yield of 2493 kg/ha over the parent rice variety, MTU 1010 (1912kg/ha) under coastal salinity stress.
This newly developed variety is suitable to be grown in Andhra Pradesh, Telangana, Karnataka, Tamil Nadu, Puducherry, Kerala, Chhattisgarh, Maharashtra, Madhya Pradesh, Odisha, Jharkhand, Bihar, Uttar Pradesh, and West Bengal.
The government said that cultivation of these varieties in about 5 million hectares of the recommended area will produce 4.5 million tonnes of additional paddy (about 3 mt in terms of rice) and greenhouse gas emissions will be reduced by 20 per cent (32000 tonnes).
In addition, due to the reduction in the duration of 20 days, three irrigations will be saved resulting in saving of a total of 7,500 million cubic meters of irrigation water, which can be used for other crops.
The development of these two varieties using genome editing technology has paved the way of using this innovative method in other crops too for higher yields, climate resilience and improved quality to achieve the targets of Viksit Bharat, ICAR said. Under the budget announcement 2023-24, the government has allocated ₹500 crore for genome editing in agricultural crops.
There are few concerns about the Intellectual Property Rights of the technology which are being looked after and will be resolved in coming times, it added.
Genome editing technology (CRISPR-Cas) is a precision mutagenesis tool to create novel and desirable variants of a native gene(s) present in a living organism. The final products of two variants of genome editing technology, namely, Site Directed Nuclease 1 (SDN 1) and Site Directed Nuclease 2 (SDN 2), are treated as free from regulation.
In SDN1 and SDN 2 type of genome editing, a native gene is mutated in its native location to create its alternative form called allele with a desirable altered expression and function. The mutants created by SDN1 and SDN 2 approaches are free of exogenous introduced DNA. These mutants are alike and indistinguishable from spontaneous or induced mutants. Hence, exempted from biosafety regulation of Rules 7-11 of Rules 1989 under Environment (Protection) Act 1986.