First Herbicide-tolerant & Non-GM rice varieties

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    In News 

    • Recently, the Prime Minister of India officially released new varieties of rice named ‘Pusa Basmati 1979 ‘and ‘Pusa Basmati 1985’.

    About 

    • The Indian Agricultural Research Institute (IARI) developed the country’s first-ever non-GM (genetically modified) herbicide-tolerant rice varieties.
    • The varieties contain a mutated acetolactate synthase (ALS) gene making it possible for farmers to spray Imazethapyr, a broad-spectrum herbicide, to control weeds. 
    • These varieties can be directly seeded and significantly save water and labour compared to conventional transplanting.
    • Development: Both Pusa Basmati 1979 and 1985 have been bred by crossing existing popular varieties — Pusa 1121 and Pusa 1509, respectively — with ‘Robin’. 
      • The latter is a mutant line derived from Nagina 22, an upland drought-tolerant rice variety. The mutant was identified for Imazethapyr-tolerance by S Robin, a rice breeder from Tamil Nadu Agricultural University in Coimbatore.

    Significance and need

    • Paddy transplantation is both labour- and water-intensive. The field where the seedlings are transplanted has to be “puddled” or tilled in standing water. 
      • For the first three weeks or so after transplanting, the plants are irrigated almost daily to maintain a water depth of 4-5 cm. 
    • Farmers continue giving water every two to three days even for the next four-five weeks when the crop is in tillering (stem development) stage.
    • Water is a natural herbicide that takes care of weeds in the paddy crop’s early growth period. 
    • The new varieties simply replace water with Imazethapyr and there’s no need for nursery, puddling, transplanting and flooding of fields.

    What is Direct Seeding of Rice (DSR)?

    • It is a method under which pre-germinated seeds are directly drilled into the field by a tractor-powered machine.
    • There is no nursery preparation or transplantation involved in this method. 
    • This water is replaced by real chemical herbicides and farmers have to only level their land and give one pre-sowing irrigation.
    • The Punjab Agricultural University (PAU) in Ludhiana has developed a ‘Lucky Seed Drill’ that can both sow seeds and simultaneously spray herbicides to control weeds. 

    Advantages 

    • Water savings because the first irrigation (apart from the pre-sowing rain) under DSR is necessary only 21 days after sowing. 
    • Less requirement of labour.  
    • Reduction in methane emissions and global warming potential
    • Little disturbance to soil structure
    • Enhanced system productivity

    Disadvantage 

    • The main issue is the availability of herbicides.
    • The seed requirement for DSR is also higher than transplanting. 
    •  Land levelling is compulsory in DSR, therefore, increases the cost.
    • In the DSR technique plants have to come out properly before the monsoon rains arrive, early sowing is required.
    • The DSR method is not suitable on certain types of soil and in such fields only transplanting methods work.

    Difference Between DSR & Normal Transplantation

    • In transplanting, farmers prepare nurseries where the paddy seeds are first sown and raised into young plants. These seedlings are then uprooted and replanted 25-35 days later in the main field.

    Present Status of direct seeding of rice 

    • The government is promoting DSR during the Kharif season this year to conserve 10 to 15 per cent of irrigation water as compared to the puddle transplanted rice. 
    • The promotion of DSR will lead to the conservation of groundwater, therefore, reduced power consumption and save farmers from a labour shortage. 
    • Farmers in Punjab and Haryana are already adopting direct seeding of rice (DSR) in response to labour shortages and depleting water tables. This year alone, roughly 6 lakh of the total 44.3 lakh hectares area under paddy in the two states has come under DSR.
    • DSR cultivation is currently based on two herbicides, Pendimethalin (applied within 72 hours of sowing) and Bispyribac-sodium (after 18-20 days).
      • These are costlier than Imazethapyr (Rs 1,500 versus Rs 300/acre). Imazethapyr, moreover, has a wider weed-control range and is safer, as the ALS gene isn’t present in humans and mammals. Even in the herbicide-tolerant rice, the chemical will target only the weeds.”
    • Transplantation in paddy typically requires about 30 irrigations, each consuming some 5 hectare-cm of water (one hectare-cm equal 100,000 litres). Puddling alone takes up about 15 hectare-cm. 
    • In all, DSR is estimated to need 30 per cent less water, save Rs 3,000 per acre in transplantation labour charges, and also 10-15 days’ time due to no nursery preparation.

    About Kharif Crops 

    • Kharif crops are grown with the onset of monsoon in different parts of the country and these are harvested in September-October.
    • Important crops grown during this season are paddy, maize, jowar, bajra, tur (arhar), moong, urad, cotton, jute, groundnut and soya bean.
    • Some of the most important rice-growing regions are Assam, West Bengal, coastal regions of Odisha, Andhra Pradesh, Telangana, Tamil Nadu, Kerala and Maharashtra, particularly the (Konkan coast) along with Uttar Pradesh and Bihar. Recently, paddy has also become an important crop of Punjab and Haryana. In states like Assam, West Bengal and Odisha.

    Genetically Modified Organisms (GMOs)-

    • It can be defined as organisms (i.e. plants, animals or microorganisms) in which the genetic material (DNA) has been altered in a way that does not occur naturally by mating and/or natural recombination
    • The technology is often called “modern biotechnology” or “gene technology”, sometimes also “recombinant DNA technology” or “genetic engineering”.
    •  It allows selected individual genes to be transferred from one organism into another, also between non-related species. 

    Source: IE