India’s first-ever non-GM (genetically modified) herbicide-tolerant rice varieties were officially announced by the Prime Minister, Narendra Modi.
The varieties — Pusa Basmati 1979 and Pusa Basmati 1985 — contain a mutated acetolactate synthase (ALS) gene making it possible for farmers to spray Imazethapyr, a broad-spectrum herbicide, to control weeds.
Both the rice varieties were developed by scientists at the Indian Agricultural Research Institute (IARI). They require significantly less water and need less labour to grow compared to conventional transplanting as they can be directly seeded.
This dispenses with the need to prepare nurseries where paddy seeds are first raised into young plants, before being uprooted and replanted 25-35 days later in the main field.
Transplanting paddy can be both labour- and water-intensive. The field where the seedlings are transplanted needs 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-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. You can sow paddy directly, just like wheat,” said A K Singh, director of IARI.
“This variety of rice has herbicide tolerance through mutation breeding, not GM. There isn’t any foreign gene here,” Singh pointed out.
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. Already, farmers in Punjab and Haryana have been using 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.