From UPSC perspective, the following things are important :
Prelims level : Not much
Mains level : Paper 3- Bt cotton
After almost 20 years of adoption of Bt cotton in India, its time to review the claimed benefits of the Bt.
Hybrid cotton seeds and issues
- Until the 20th century the indigenous ‘desi’ variety, Gossypium arboreum was used.
- From the 1990s, hybrid varieties of G. hirsutum were promoted.
- These hybrids cannot resist a variety of local pests and require more fertilizers and pesticides.
- Cotton suffers from plenty of infestation from moth pests such as the Pink Bollworm (PBW) and sap-sucking (Hemipteran) pests such as aphids and mealy bugs.
- With increasing pressure to buy hybrid seeds, the indigenous varieties have lost out over the years.
Resistant pests and introduction of Bt cotton
- The increasing use of synthetic man-made pesticides to control pests and the rising acreage under the American long-duration cotton led to the emergence of resistant pests.
- Resistant Pink and even American Bollworm (ABW), a minor pest in the past, began increasing, leading to a growing use of a variety of pesticides.
- Rising debts and reducing yields, coupled with increasing insect resistance, worsened the plight of cotton farmers.
- It was in this setting that Bt cotton was introduced in India in 2002.
What is Bt cotton
- The plant containing the pesticide gene from the bacteria Bacillus thuringiensis (Bt), has been grown in India for about twenty years.
- This pesticide, now produced in each Bt plant cell, ought to protect the plant from bollworm, thereby increasing yields and reducing insecticide spraying on the cotton plant.
Review of the utility of Bt cotton
- Review was published in the scientific journal Nature Plants, analysing the entire picture of the use of Bt cotton in India.
- Earlier studies had attributed to Bt the tripling of cotton yield between 2002-2014 in India.
- However, one detail that raises concerns over such a conclusion was that yield differences between farmers who were the early adopters of Bt cotton and those who were not suffered from selection bias.
- Controlling for such bias showed (in 2012) that the contribution of Bt cotton to yield increase was only about 4% each year.
- Since yields vary annually by over 10%, the benefits claimed were dubious.
- There are discrepancies between yield and the deployment of Bt cotton.
- For instance, the Bt acreage was only 3.4% of the total cotton area in 2003, not sufficient to credit it for the 61% increase in yield in 2003-2004.
- The rise in cotton yields can be explained by improvements in irrigation, for instance in Gujarat, and a dramatic growth across the country in the use of fertilizers.
- The PBW developed a resistance by 2009 in India. In a few years, the situation was dreadful.
- A technology that works in the lab may fail in fields since real-world success hinges on multiple factors.
- The cost of ignoring ‘desi’ varieties for decades has been high for India.
- Research suggests that with pure-line cotton varieties, high density planting, and short season plants, cotton yields in India can be good and stand a better chance at withstanding the vagaries of climate change.
- But government backing for resources, infrastructure and seeds is essential.
It is time to pay attention to science and acknowledge that Bt cotton has failed in India, and not enter into further misadventures with other Bt crops such as brinjal or herbicide resistance.