The unauthorised herbicide-tolerant Bt (HTBt) cotton cultivation has spread to around 24-30 per cent of the acreage under the fibre crop in the country, with labour shortage and rising weed control costs driving the adoption in about 65-72 lakh acres during kharif 2025 season, says a study.

Conducted by the South Asia Biotechnology Centre (SABC) and supported by the Federation of Seed Industry of India and the National Seed Association of India (NSAI), the study estimated the value of the informal HTBt cotton seed market in the country at ₹820-880 crore.

Based on field surveys and stakeholder interactions across 16 cotton-growing districts in Maharashtra, Telangana, Andhra Pradesh and Rajasthan, the study found that farmers were increasingly turning to unauthorized seeds to address acute labour shortages, rising cultivation costs and the need for more efficient weed management.

As a result, the consumption of glyphosate, a key herbicide that is a central pillar of the HTBt technology, has increased alongside the spread of the cotton variety. Glyphosate-based weed management costs farmers around ₹750-850 an acre, compared with ₹12,000-15,000 for manual labour, making herbicide-tolerant cotton an attractive option for growers, the study said.

The usage of glyphosate has increased by 26 per cent from 27,271 KL (kilo litres) in 2024-25 to 35,642 KL in 2025-26, corroborated by import data, and that the herbicide is increasingly being sourced through underground networks in bulk, upto 20 litre drums, it said.

Maharashtra has emerged as the epicentre of HTBt cotton cultivation, with adoption estimated at 58 per cent and reaching 76 per cent in Yavatmal district. Adoption was also high in Telangana, at 66 per cent, and Andhra Pradesh, at 49 per cent, with rates reaching 82 per cent in Mahabubabad and 75 per cent in Kurnool, respectively. In contrast, adoption remained negligible in Rajasthan, where the shorter crop duration and relatively manageable weed pressure reduced the incentive to adopt the technology.

The study found that 98.2 per cent of samples (223 of 227) tested positive for at least one genetically modified (GM) trait. While Cry1Ac and Cry2Ab genes, associated with Bollgard-II technology, remained dominant at 95.1 per cent and 84.1 per cent, respectively, the unapproved herbicide-tolerance gene CP4EPSPS was detected in 72.7 per cent of samples and the insect-resistance gene Vip3A in 53.7 per cent, indicating the growing presence of additional traits in cotton cultivation.

The study identified 14 combinations of four genes, indicating a shift towards multi-trait cotton hybrids across major growing regions. Quadruple stacks containing Cry1Ac, Cry2Ab, CP4EPSPS and Vip3A accounted for 41.9 per cent of samples, while triple and double stacks accounted for 30.4 per cent and 21.1 per cent, respectively. Overall, 72.7 per cent of samples carried the herbicide-tolerance gene CP4EPSPS, while many also contained the next-generation insect-resistance gene Vip3A, indicating the widespread presence of these traits across cotton-growing belts.

Further, the expansion of HTBt cotton is also affecting the market for approved seeds. Sales of Bollgard-II (BG-II) seeds containing Cry1Ac and Cry2Ab insect-resistance traits declined 22.3 per cent across the country between 2022 and 2026, it said.

The findings raise concerns about seed quality, biosafety and the development of resistance to herbicides and insect-control technologies. Since unauthorised seeds are sold outside regulated channels, farmers may have limited recourse if the seed fails to perform as expected.

The study attributed the spread partly to regulatory delays and called for a transparent, time-bound approval process for next-generation cotton technologies. It recommended that the government fast-track approval of BG-II-RRF cotton to provide farmers access to validated seeds through legitimate channels.

Bhagirath Chaudhary, Founder Director, SABC, said based on the findings of this study, there is a clear need for an integrated and forward-looking approach including the establishment of a transparent policy framework, a coherent national strategy and a robust and functional regulatory system.

“Such a system must be capable of effectively evaluating biosafety, agronomic performance and stewardship requirements, while ensuring that only approved GM cotton technologies reach farmers in a timely and regulated manner, with due emphasis on seed quality and scientific resistance management of pests and weeds at the field level. Further, it underscores the need to align R&D innovation, regulation, scientific outreach and farmer welfare within a predictable, time-bound and responsive policy and regulatory ecosystem,” he said.

Published on October 21, 2026