Imidazolinone-resistant (IMI-resistant) mustard
Why in News?
Imidazolinone-resistant (IMI-resistant) mustard is in the news because India is rolling out its large-scale cultivation for the upcoming 2026–27 rabi sowing season (October to April).
The Target Threat: Orobanche
- Parasitic Mechanism: Orobanche is an obligate root parasite that locks onto the roots of the mustard plant to sap its water and essential nutrients.
- Regional Damage: It remains a hidden, underground threat that dramatically suppresses crop yields across the arid agricultural belts of North India.
Breeding Technology & Regulatory Status
- Non-GM Status: The herbicide tolerance trait was engineered through conventional plant breeding and mutation breeding techniques rather than transgenic Genetically Modified (GM) engineering.
- Regulatory Clearance: Because it is non-GM, the seed avoids the rigid bans and regulatory conflicts often associated with transgenic herbicide-tolerant variants in India.
- The Biological Mechanism: The breeding alters a single DNA sequence to mutate the Acetolactate Synthase (ALS) enzyme. This mutation lets the mustard plant survive chemical sprays while the target weeds are killed.
Core Advantages for Farmers
- High Post-Emergence Control: It allows farmers to safely apply post-emergence imidazolinone (IMI) herbicides across the field without harming the mustard crop itself.
- Labour and Cost Savings: Chemical weed suppression reduces the intensive physical labour and high costs required for manual weeding during peak seasonal shifts.
- Enhanced Productivity: By neutralizing resource-draining parasites early, it optimizes overall output to support national oilseed self-reliance goals.
Ecosystem Risks and Management Warnings
- Superweed Risk: Experts warn that continuous, year-after-year reliance on a single chemical group creates a "strong directional selection". This risk could push Orobanche to mutate into chemical-resistant "superweeds".
- Integrated Farming Mandate: To keep the technology viable, agricultural policies stress that the hybrids must be integrated into a diverse strategy including crop rotation, alternating herbicide modes of action, and targeted manual weeding.
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