Bt hybrid (Bollgard II event)
Sold under many company brand names on the same GEAC-approved event — the built-in protection is against the bollworm complex generally, and stalk destruction after harvest still matters for pink bollworm.
Quick facts
- Crop
- Cotton
- Type
- Hybrid
- Season
- Kharif
- Maturity period
- 160–170 days
- Expected yield
- 18–22 q/ha (seed cotton)
- Suitable soil
- Clay / black soil
- Release
- GEAC approval 2006 · event licensed from Mahyco Monsanto Biotech, sold by many companies under their own hybrid names
About this variety
"Bt hybrid (Bollgard II event)" is not one ICAR-released variety — it is a class of hybrids from many seed companies that all carry the same Bollgard II genetic event, licensed from Mahyco Monsanto Biotech and approved by India's Genetic Engineering Appraisal Committee (GEAC) for commercial release in 2006. The event stacks two Bt genes, Cry1Ac and Cry2Ab, in the cotton plant's own tissue, giving built-in protection against the bollworm complex (American, spotted and — originally — pink bollworm). ICAR-CICR, Nagpur has been the government's Bt Referral Laboratory since 2005, testing seed lots for the presence of the Cry genes.
Key characteristics
Yield & maturity
Maturity period
160–170 days
Expected yield
18–22 q/ha (seed cotton)
Actual yield depends on sowing time, soil, irrigation, weather, seed quality and crop management.
Pest & disease considerations
Major diseases
- Bollworm complex — not pink bollworm, which has developed resistance
Management notes
- Grow the mandatory refuge — 5 border rows of non-Bt cotton, or 20% of the field area, whichever is more — around every Bt hybrid block; this is the Government of India stewardship requirement, not optional
- Destroy and remove cotton stalks right after the last picking — pink bollworm overwinters in old stalks and unpicked bolls, and this is now the main defence since the pest developed resistance to Bollgard II by around 2015
Advantages & considerations
Why farmers may choose it
- Built-in protection against the bollworm complex reduces the number of sprays needed for that pest group specifically
- Wide choice of company hybrids on the same event, adapted to different regions and soils
Things to consider
- Pink bollworm resistance to Bollgard II is now widespread — the technology no longer reliably protects against this particular bollworm species, only the American and spotted bollworm
- Higher seed cost than a non-Bt hybrid or open-pollinated variety, and no built-in protection against sucking pests (jassids, whitefly, thrips, mealybug) at all
- Skipping the refuge requirement accelerates resistance development for everyone growing Bt cotton in the area, not just your own field
Suitable regions
States this variety is recommended for — check locally, since a state can have more than one recommended zone.
- Gujarat
- Maharashtra
- Telangana
- Andhra Pradesh
- Punjab
Frequently asked questions
Is Bt cotton the same in every company’s hybrid?
The underlying genetic event (Bollgard II, carrying Cry1Ac and Cry2Ab) is usually the same, licensed from Mahyco Monsanto Biotech — but it is bred into different parent lines by different companies, so agronomic traits like duration, canopy and regional suitability vary by brand.
Does Bt cotton still protect against pink bollworm?
Not reliably. Field-level resistance to Bollgard II was first reported by CICR around 2015, driven largely by inadequate refuge planting — stalk destruction after harvest and refuge compliance now matter more than the Bt trait itself for this pest.
How much refuge area does Bt cotton need?
5 border rows of non-Bt cotton, or 20% of the total field area, whichever is more — this is the Government of India stewardship requirement for every Bt hybrid.