PM releases First non-GM Herbicide-Tolerant Rice Varieties
Science & Technology
5th Oct, 2021
To counter the twin challenges of climate change and malnutrition, PM Narendra Modi launched 35 new indigenously-developed crop varieties developed by ICAR. The one that is making it into the news is the country’s first-ever non-GM (genetically modified) herbicide-tolerant rice varieties.
- It is alarming to know that, about 45 percent of total irrigation water in India is used for rice cultivation.
- And rampant use of herbicides and pesticides is not only causing the problem to our health but is also negatively affecting our exports.
- This needs to be addressed and the country’s first-ever non-GM herbicide-tolerant rice varieties can provide a sustainable solution.
- These are not only disease-resistant but drought and herbicide-tolerant too.
About New Varieties of Rice:
- It is the country’s first-ever non-GM (genetically modified) herbicide-tolerant rice varieties (Pusa Basmati 1979 and Pusa Basmati 1985) that have been developed by the Indian Agricultural Research Institute (IARI).
- These varieties have been developed by crossing over Pusa 1121&Pusa 1509 with Robin (It is a drought-tolerant, heat-tolerant and deep-rooted variety derived from Nagina 22.)
- Instead of going GM techniques, ICMR has developed it through mutation breeding. This ensures that no foreign genesare in the new varieties.
- Both the newly developed varieties contain a mutated acetolactate synthase (ALS) gene, which enables farmers to spray Imazethapyr, which is a cheaper and broad-spectrum herbicide, to control weeds.
Mechanism of its herbicide-tolerance:
- Imazethapyr is used by the farmers to remove broadleaf, grassy and sedge weeds. But it cannot be used on normal rice varieties as it is the incapability to distinguish between weeds and crops, and it might kill the paddy crop itself.
- But the newly developed variety has mutated acetolactate synthase (ALS) gene, the herbicide, in this case,do not bind with the enzyme that this mutated gene produces which inhibits the production of amino acids and hence saves the paddy crop, as the plant continues to grow and only the weed gets killed.This mechanism is known as herbicidetolerance through mutation breeding.
- There is no foreign gene is involved in the whole process. The plant can now “tolerate” the application of herbicide and selective action of herbicide can be made possible.
Efficient use of water and reduction in labour:
- As the newly developed varieties can be directly seeded, it can save the labour and water input to a great extent as compared to conventional transplanting varieties.
- This is made possible because, in the new varieties, the application of herbicides like Imazethapyr is possible, which eradicate a wide range of weeds.
- In conventional transplanting varieties, the direct application of herbicides is not possible as it cannot distinguish between the rice plants and the weeds. This is one of the primary reasons why paddy seeds are first grown as young plants before planting in the fields.
- Standing water in the nursery provides a natural barrier towards eliminating weeds. But this process is both water and labour intensive as the young seedling is supposed to be maintained in standing water up to a depth of 5 cm for about 25-35 days.
- IARI has stated that the new varieties are herbicide-tolerant and the chemical application will only target weeds, thereby allowing farmers to sow paddy directly just like any other crop.
|Direct Seeding Techniques (DSR) requires 30 per cent less water for cultivation, saves up to Rs 3,000 per acre in transplantation in labour charges and about 10 to 15 days in cultivation as it doesn’t need to prepare a nursery.
Why this is better than GM herbicide-resistant rice?
- Herbicide-resistant (GM) varieties of rice do have the potential to improve the efficiency of weed management but it also comes with risks.
- There is a risk of potential transfer of genes from Herbicide-resistant varieties to their wild relative. This can result in hybrid varieties of its wild and weedy relative.
- The chance of such occurrences is higher in India because the flowering times of cultivated rice and its wild relatives overlap.
- Such a gene can result in loss of native biodiversity and impact crop invasiveness.
- Herbicide-resistant (GM) varieties of rice may contribute to the problems of crop volunteers and the evolution of herbicide resistance.
- It gives us a cheaper option, as Imazethapyr (herbicide) can be used as a pesticide which is cheaper than Pendimethalin and Bispyribac-sodium.
- Not only Imazethapyr has a wider range of weed control, but it is alsomuch safer because the mutated ALS gene in the two newly developed varieties is not present in humans or animals.
Pre-emergent herbicides: These are chemicals applied before germination. It can also be applied immediately after sowing using ordinary seed drills. E.g.: pendimethalin.
Post-emergent herbicides: these chemicals are sprayed 20-25 days after the sowing of the seeds. E.g.: Bispyribac-sodium, Fenoxaprop-p-ethyl, etc.
Some Facts about Rice:
- It is mainly a tropical crop and a hot and humid climate is most suitable.
- It requires an average temperature of 20°C to 35°C and annual rainfall of 150 cm.
- Rice is a Kharif crop in India that is sown during the southwest monsoon.The sowing time ofrice is June-July and it is harvested in the months of November-December.
- It requires well-drained fertile loamy and clayey loamy soil. Ganga-Sutlej plains and the black soil region of the Deccan are the most suited types for its cultivation.
Sustainable methods of Rice Cultivation:
- Fish- Rice farming method: In this method, the fish are reared in the flooded rice field. This not only reduces the methane emission from the rice field but also provide an alternate source of income to the farmer.
- System of Rice Intensification method:In this method, the seedling is planted singly at wider spacing and intermittent irrigation is deployed which adequately keeps the soil moist but not inundated. This method works by reducing the competition among plants and improving the oxygen supply. But it is a labour-intensive method.
We need to opt for both traditional farming and new agricultural practices based on technological advancements. It is time that we fine-tune the balance between the ‘back to basic’ and ‘march to future’ approaches. ICAR has played a pioneering role during Green Revolution and has been continuously been contributingtoIndian agriculture through its research and technology development. The development of crops which are climate-resilient, fortified and uses less water, is importantnot only for the progress of agriculture but alsoto address the twin challenge of climate change and malnutrition.