Both the varieties contain a mutated acetolactate synthase (ALS) gene helping farmers to spray Imazethapyr, a broad-spectrum herbicide, to control weeds.
A non-Genetically Modified (GM) rice variety that is tolerant to herbicide use, indigenously made in India is a reality now. The Indian Agricultural Research Institute has come up with two varieties of these rice-Pusa basmati 1979 and Pusa Basmati 1985that can be directly seeded, need less money and labour for planting compared to conventional rice farming.
Both the varieties contain a mutated acetolactate synthase (ALS) gene helping farmers to spray Imazethapyr, a broad-spectrum herbicide, to control weeds. Both he varieties were launched by the PM today.
For conventional paddy cultivation farmers need to transplant the seed after which they are “puddled” and tilled in standing water . The plants are irrigated frequently for the first three weeks to maintain water depth of 4-5 cm. Watering the plant is required every alternate day in the next four-five weeks during the stem development stage, making rice farming labour and water intensive. In this new rice variety with Imazethapyr, the requirement of transplanting, nursery puddling and flooding fields is removed and they can be sowed directly just like wheat, A K Singh, director of IARI informed.
Imazethapyr, used to remove broadleaf, grassy and sedge weeds cannot be used on normal rice varieties as it cannot distinguish between weeds and crops and might end up destroying paddy. But for the new varieties with its ALS gene the herbicide binds with the enzymes produced inhibiting production of amino acids. This mechanism is called herbicide-tolerance through mutation breeding . There is no involvement of a foreign gene
Pusa Basmati 1979 and 1985 were made after cross breeding existing popular varieties —Pusa 1509 and Pusa 1121 with ‘Robin’ derived from a doubt-tolerant rice variety. The Imazethapyr-tolerance rice variety was identified by S Robin, a rice breeder from Tamil Nadu Agricultural University in Coimbatore.
Meanwhile in Punjab, farmers are already direct seeding rice due to depleting water tables and labour shortage. Around 6 lakh hectares of agricultural land in the state has started direct seeding (DSR) technique for paddy cultivation. 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.
DSR at present is based on Bispyribac-sodium, Pendimethalin both utilized in different stages and are more expensive than Imazethapyr, which has wider weed control range and is safer since the ALS gene unique to the rice varieties is not present in humans or animals.