Complete UPSC Notes — What is Bt cotton, how Cry protein kills bollworms (diagram), Bollgard I vs II, India's cotton revolution (2002–2013), pink bollworm resistance crisis (2014–present), HtBt cotton controversy, production decline to 29.5M bales (2024–25). With PYQs and MCQs.
Imagine a cotton plant that has a built-in bodyguard. This bodyguard doesn't carry a weapon from outside — instead, the plant itself produces a protein that poisons bollworms the moment they try to eat it. How? Scientists took a gene from a soil bacterium called Bacillus thuringiensis (Bt) and inserted it into cotton's DNA. Now the cotton plant makes a Cry protein — a crystal toxin that specifically kills bollworm caterpillars. No need to spray pesticides. The plant defends itself.
2002
Year Bt Cotton was approved in India (GEAC)
95%
Share of India's cotton area under Bt hybrids at peak
29.5M
Cotton bales expected in 2024-25 (down from 39.8M peak)
60M+
People dependent on cotton in India (farming, processing, textiles)
Section 02 — How Bt Toxin Works
🦠 How Does the Cry Protein Kill Bollworms?
How Bt Cotton Kills Bollworms — Step by Step
🌿① Bt Cotton PlantPlant produces Cry protein (crystal toxin) in its cells — from the Bt gene
→
🐛② Bollworm Eats LeafCaterpillar (bollworm larvae) feeds on the cotton leaf containing Cry protein
→
⚡③ Toxin ActivatesInsect gut is alkaline (pH 9-10) → Cry protein gets activated into its toxic form
→
💥④ Gut DestroyedActivated toxin punches holes in insect's gut wall → contents leak out → insect stops feeding
→
💀⑤ Insect DiesBollworm dies within 2-3 days. Cotton plant survives. No pesticide needed!
📌 Why is it safe for humans? Human stomachs are acidic (pH 1.5-3.5). The Cry protein only activates in alkaline conditions (pH 9-10) — found ONLY in insect guts. In your stomach, the Cry protein is simply digested like any other protein (like chicken or dal). Biosafety tests confirmed: no adverse effects on goats, cows, buffaloes, fish, poultry, or humans.
Section 03
📊 Bollgard I vs Bollgard II
🌿 Bollgard I (1996/2002)
Gene
Cry1Ac (single gene)
Year
USA: 1996. India: 2002
Kills
Tobacco budworm, pink bollworm, American bollworm
Developer
Monsanto (now Bayer)
Status
Largely replaced by Bollgard II
🌿🌿 Bollgard II (2003/2006)
Genes
Cry1Ac + Cry2Ab (two genes — broader protection)
Year
USA: 2003. India: 2006
Kills
All bollworms + additional Lepidopteran pests
Developer
Monsanto-Mahyco (now Bayer)
Status
Dominant variety in India (~95% of cotton area)
⚠️ The Problem: By 2014, pink bollworm (PBW) began developing resistance to both Cry1Ac AND Cry2Ab in central and southern India. First reported: Amreli district, Gujarat (2011). By 2017-18, resistance was widespread across Gujarat, Maharashtra, Madhya Pradesh, Andhra Pradesh, Telangana, and Karnataka. This is the core of India's Bt cotton crisis today.
Section 04 — India's Story
📈📉 India's Bt Cotton Journey — Rise & Decline
2002
Bt Cotton approved by GEAC for commercial cultivation — India's first and only GM crop. Monsanto-Mahyco's Bollgard I (Cry1Ac).
2006
Bollgard II introduced (Cry1Ac + Cry2Ab). Rapid adoption. Cotton area under Bt hybrids grows to 95%.
2013-14
Peak production: 39.8 million bales. Yield: 566 kg/ha. India becomes world's largest cotton producer. Massive reduction in pesticide use. Women's employment surges.
2011
First resistance report: Pink bollworm resistance to Bt proteins documented in Amreli, Gujarat.
2017-18
Widespread PBW resistance across Gujarat, Maharashtra, MP, AP, Telangana, Karnataka. Pests now infest crops as early as 40-45 days after sowing.
2022-23
Production drops to 343.5 lakh bales (34.35 million). Yield: 447 kg/ha — well below peak.
2024-25
Further decline: Production expected at ~29.5 million bales. India becomes net cotton importer ($1.04 billion imports). TSV virus adds to crisis. Agriculture Minister calls meeting (July 2025).
Section 05 — Controversy
⚠️ HtBt Cotton — The Illegal GM Variant
📌 What is HtBt Cotton? It adds a second modification to Bt cotton — the Cp4-EPSPS gene from Agrobacterium tumefaciens — making the plant resistant to the herbicide glufosinate/glyphosate. Farmers spray herbicide → weeds die → Bt cotton survives. This is NOT approved by GEAC but is illegally cultivated on 15-25% of India's cotton acreage (Federation of Seed Industry of India estimate).
Why Farmers Want It
Dramatically reduces labour cost for weeding — especially important as rural labour becomes scarce. One herbicide spray replaces weeks of manual weeding. Higher effective yield because less crop damage from weeding.
Why It's Dangerous
Glyphosate concerns: IARC (WHO) classified glyphosate as "probably carcinogenic." Superweeds: Herbicide resistance can transfer to nearby weeds via pollen → herbicide-resistant weeds. No quality control: Illegal seeds sold under fake brand names → no seed quality guarantee → environmental risk. Revenue loss: Government loses tax revenue, legitimate seed companies lose sales.
Section 06 — PYQs
🧾 UPSC Previous Year Questions
UPSC 2012Prelims
Bt-brinjal is created by inserting a gene from:
1.Bt brinjal has been created by inserting a gene from a soil fungus into its genome.
2.The seeds of Bt brinjal are terminator seeds and therefore, the farmers have to buy the seeds before every season from the seed companies.
3.There is an apprehension that the consumption of Bt brinjal may have adverse impact on health.
4.There is some concern that the introduction of Bt brinjal may have adverse effect on the biodiversity.
Which of the statements given above is/are correct?
A1, 2 and 3 only
B2 and 3 only
C3 and 4 only
D1, 2, 3 and 4
📌 Explanation Answer: (c) 3 and 4 only. Statement 1 ✗ — Bt gene is from a soil bacterium (Bacillus thuringiensis), NOT a fungus. Statement 2 ✗ — Terminator seed technology is a proposed concept and has NOT been proven or used in Bt brinjal. Bt brinjal seeds CAN be saved and replanted. Statement 3 ✓ — There IS apprehension about health impacts of consuming GM food crops (this was a key reason for the moratorium). Statement 4 ✓ — India is a centre of origin for brinjal → introducing Bt genes could contaminate wild varieties → biodiversity concern.
UPSC 2001Prelims
A toxin gene from which bacterium has been transferred to Monsanto's insect-resistant transgenic cotton?
ABacillus subtilis
BBacillus thuringiensis
CBacillus amyloliquefaciens
DBacillus globisporus
📌 Explanation Answer: (b) Bacillus thuringiensis. The "Bt" in Bt cotton = Bacillus thuringiensis. The Cry toxin gene was transferred from this soil bacterium into cotton. Note: B. amyloliquefaciens (option c) is the source of barnase/barstar genes in GM mustard — a different GM crop entirely.
UPSC 2021Prelims
Bollgard I and Bollgard II technologies are mentioned in the context of:
AClonal propagation of crop plants
BDeveloping genetically modified crop plants
CProduction of plant growth substances
DProduction of biofertilizers
📌 Explanation Answer: (b) Developing genetically modified crop plants. Bollgard I (Cry1Ac) and Bollgard II (Cry1Ac + Cry2Ab) are Monsanto's Bt cotton technologies — both are GM (transgenic) cotton varieties engineered for bollworm resistance.
Bt Cotton = India's ONLY approved GM crop. Approved 2002. GEAC under MoEFCC (not Agriculture!).
BG I
Bollgard I = Cry1Ac (one gene). Introduced in India 2002.
BG II
Bollgard II = Cry1Ac + Cry2Ab (two genes). Introduced 2006. Broader pest protection. UPSC 2021!
PEAK
2013-14: 39.8M bales, 566 kg/ha. India = world's largest cotton producer. Peak performance.
CRISIS
Post-2014: Pink bollworm resistance → production drops. 2024-25: ~29.5M bales. India became net cotton importer.
HOW
Cry protein → insect eats leaf → alkaline gut activates toxin → holes in gut wall → insect dies. Acidic human stomach = no effect.
HtBt
Herbicide-tolerant Bt cotton. Cp4-EPSPS gene from Agrobacterium. NOT approved but illegally grown (15-25%). Glyphosate concern.
TERM
Terminator seeds = NOT used in Bt cotton/brinjal. It's a proposed concept, not reality. UPSC 2012 trap!
60M
60 million+ people in India depend on cotton (farming, processing, textiles). Cotton = "White Gold."
Section 08
❓ FAQs
Why did pink bollworm develop resistance to Bt cotton?
In countries like the USA, farmers plant "refuge areas" — patches of non-Bt cotton alongside Bt fields. This ensures some bollworms grow on normal cotton (without Bt exposure), remain susceptible to Bt, and mate with resistant individuals — diluting resistance genes in the population. India's problem: smallholder farms (average 1.5 hectares) don't have enough space for refuges. With 95% of India's cotton area under Bt hybrids, virtually every bollworm is exposed to Bt proteins from birth → strong selection pressure → resistance evolved rapidly. By 2014-17, pink bollworm populations in central and southern India could survive on Bt cotton.
Is Bt cotton safe to eat?
Cotton is primarily grown for fibre, not food. However, cottonseed is used for oil and animal feed. Extensive biosafety testing by ICAR showed no adverse effects on goats, cows, buffaloes, fish, and poultry fed Bt cottonseed meal. The Cry protein is digested like any other protein in mammalian (acidic) digestive systems. It is only toxic in the alkaline gut environment of specific insects. However, the safety of Bt in food crops (like Bt brinjal) remains debated — which is one reason for the moratorium.
What is India doing about the Bt cotton crisis?
In July 2025, Union Agriculture Minister convened a meeting to discuss cotton productivity decline. Key strategies being considered: (1) New pest-resistant GM varieties — expediting regulatory clearance for whitefly-resistant and PBW-resistant cotton. (2) High-Density Planting System (HDPS) — increasing plant population per unit area. (3) Kasturi Cotton branding — quality assurance with QR-code traceability for exports. (4) Mission for Cotton Productivity — a five-year plan announced with the goal to restore yields. (5) Cott-Ally platform — real-time updates on MSP, weather, pest alerts for farmers.
Section 09
🏁 Conclusion
🌿 From White Gold to Red Alert
Bt Cotton is a story in two acts. Act One (2002–2013) was a triumph: India went from a cotton importer to the world's largest producer, yields doubled, pesticide use plummeted, and 60 million livelihoods improved. It was the poster child of GM technology in a developing country.
Act Two (2014–present) is a cautionary tale: pink bollworm resistance, production decline from 39.8 million to 29.5 million bales, India becoming a net cotton importer again, and illegal HtBt cotton spreading across fields without regulatory oversight. The lesson? No technology is permanent. Pests evolve. And a country that puts 95% of its cotton in one genetic basket eventually pays the price.
For UPSC: Bt Cotton = ONLY approved GM crop (2002). Gene from Bacillus thuringiensis (BACTERIUM, not fungus!). Cry protein = kills insects via alkaline gut activation. Bollgard I = Cry1Ac. Bollgard II = Cry1Ac + Cry2Ab. GEAC = MoEFCC. Pink bollworm resistance post-2014. HtBt = illegal but widespread. Terminator seeds = NOT used (exam trap!).
