HT BASMATI RICE VARIETIES (Syllabus: GS Paper 3 – Agriculture)

Context: The Indian Council of Agricultural Research (ICAR) has commercialised herbicide-tolerant (Ht) basmati rice varieties, claiming they can control weeds in rice crops while also promoting water-saving direct seeded rice (DSR).

Herbicide-tolerant (Ht) Basmati Rice Varieties

• About: Two rice varieties–Pusa basmati (PB) 1979 and PB 1985–can be grown using direct seeding of rice (DSR) method, which significantly reduces water and labour use compared with traditional transplantation methods.
• The new rice varieties could help mitigate climate change by reducing methane emissions associated with traditional rice cultivation methods.
• Developed by: Indian Agricultural Research Institute (IARI), affiliated to the Indian Council for Agricultural Research.
• Increased Productivity: These varieties may lead to higher crop yields by minimizing yield losses due to weeds, a major biological constraint in rice production.
• Concerns Regarding Herbicide Resistance
• Herbicide Resistance: While the ALS gene mutation allows for targeted weed control using Imazethapyr herbicide, continuous use of the same herbicide can lead to weed resistance over time. 

o This could necessitate stronger herbicides and potentially select for more aggressive weed strains.

• Genetic Diversity: Promotion of Ht rice varieties (varieties containing the ALS gene) may decrease genetic diversity in Indian rice. 
• Traditional DSR System: The North Western Plains Zone historically used the Direct Seeding Rice (DSR) system, which is more water-efficient than the Transplanted Rice System (TRS).

o DSR allows farmers to grow the crop directly from seeds sown in the field, bypassing the traditional technique of transplanting seedlings from the nursery.

• Impact of Green Revolution: The introduction of high-yielding, water-intensive dwarf rice varieties during the Green Revolution led to a shift away from the DSR system towards the more water-demanding TRS. This negatively affected groundwater levels.