The weed threat to mustard, and need for new solutions, Pg19

Key Highlights:

• Orobanche aegyptiaca, a parasitic weed, is infesting mustard crops across India, particularly in Rajasthan, UP, Madhya Pradesh, Haryana, and West Bengal.
• The weed attaches to mustard plant roots, extracting nutrients and water, leading to yield reduction; Haryana farmer Kokchand Sahu saw his yields drop from 9-12 quintals/acre to 6 quintals/acre.
• South Asia Biotechnology Centre (SABC) survey indicates heavy Orobanche emergence in Haryana's Sirsa and Bhiwani districts, especially in repeatedly cultivated mustard fields.
• Mustard is India’s largest indigenous edible oil source, producing over 4 million tonnes annually, and is crucial for reducing the country's $18.3 billion edible oil imports.
• Herbicide-resistant mustard hybrids like ‘Pioneer 45S42CL’ are being used; developed by Corteva Agriscience, it tolerates imidazolinone herbicides to control Orobanche.

Detailed Insights:

• Orobanche's underground nature makes it a "hidden threat," damaging crops before its shoots emerge; a single shoot produces thousands of seeds viable for up to 20 years, causing rapid infestation.
• Traditional glyphosate herbicides are ineffective against Orobanche in normal mustard crops because they kill both the weed and the crop; current spraying levels are insufficient for enzyme blockage.
• Herbicide-resistant hybrids like ‘Pioneer 45S42CL’ offer a solution by tolerating herbicides like imazapyr, which selectively kill weeds without harming the mustard plants.
• GM mustard lines, developed by Delhi University, contain genes for resistance to glyphosate, imidazolinone, and sulfonylurea herbicides, providing a potential future solution.
• Farmers are shifting from mustard to crops like wheat and chickpea due to Orobanche infestations, despite mustard requiring fewer irrigations than wheat.

Key Concepts Involved:

• Orobanche aegyptiaca: A parasitic weed that infests mustard crops by attaching to their roots and extracting nutrients.
• Herbicide Resistance: The ability of a plant to survive exposure to herbicides that would normally kill it.
• Glyphosate: A broad-spectrum herbicide that inhibits the EPSPS enzyme, essential for plant growth.