As Indian farmers prepare to cultivate imidazolinone-resistant (IMI-resistant) mustard hybrids on a wide scale for the first time in the 2026-27 rabi season, a leading geneticist has warned that the technology must be managed with care to prevent weeds from evolving their own resistance .
The new hybrids are designed to combat a destructive root parasite called Orobanche, a major hurdle in India’s oilseed production . However, experts caution that relying on a single solution could lead to long-term failure .
The Need for a Technological Fix
India is the world’s largest importer of edible oils. In 2024-25, the country imported around 16 million tonnes at a cost of approximately Rs 1.6 lakh crore. Mustard is the country’s most vital oilseed crop to meet this demand, particularly in the arid regions of North India. However, yields have been consistently suppressed by Orobanche, a destructive root parasite that attaches to the mustard plant and drains it of water and nutrients .
Unlike genetically modified crops, these hybrids were developed through mutation breeding, a process that preserves certain natural mutations. A single change in the plant’s DNA rendered it resistant to imidazolinone (IMI) herbicides, freeing farmers to spray the chemical directly over the field. This strategy is effective against Orobanche because, as the herbicide moves through the soil and the plant, it strikes the parasite where manual weeding cannot reach .
The Trap of Mono-Chemistry
Farmers have welcomed the hybrids because they offer a solution to the weed without increasing labor demands during the critical weeding window . However, in a commentary published in the journal Current Science, University of Delhi geneticist Deepak Pental warned that the technology is not a simple trade-off where chemicals merely replace manual labour. He described it as a “challenge” requiring a variety of weed-control methods .
“If farmers rely on only one type of herbicide year after year, the ‘strong directional selection’ will lead to the emergence of resistant or less susceptible weed populations, the erosion of herbicide efficacy, and ultimately the strategic failure of the production system built around that chemistry,” Prof. Pental wrote .
He stressed that “a single herbicide mode of action cannot be the foundation of a sustainable weed management strategy in any agriculture” .
A Path to ‘Durable’ Farming
For the technology to remain viable for more than a few years, it must be part of a broader, more diverse farming strategy . Prof. Pental called for the integration of several practices:
- Rotating crops to break the weed cycle
- Using different types of herbicides with various modes of action to prevent resistance
- Continuing manual weeding to remove any weeds that survive the chemical spray
As India rolls out IMI-resistant mustard, the new challenge for the agricultural enterprise will be to ensure these powerful new tools become part of a “durable, and evolutionarily informed” programme rather than a quick fix .
