When it comes to the contribution of Bt technology towards yield increase in cotton vis-à-vis other agri-inputs, the field evidences squarely differ from the findings of Keshav R Kranthi and Glenn Davis Stone, published in Nature Plants, March 2020, and their contentions as published in the article ‘Bt cotton only increased cost of cultivation: Study’, in BusinessLine dated March 18, 2020.
In the latter, Kranthi articulated three ‘misconceptions’: i) Bt cotton alone increased yields, ii) Cotton hybrids are superior to the other varieties in providing yields, and iii) No increase in yield is possible without new Bt/GM technology.
The latter two points do not find mention in the controversial work of Kranthi and Stone. Even the first ‘misconception’ is prised from between the lines, if not rejected outright. Kranthi contended that cotton yield had started rising even before Bt cotton was introduced, due to other agri-inputs such as novel insecticides that could control the American bollworm.
Comparing yield growth
In fact, the yield growth rate was just half in the pre-BT cotton period (from 1993-94 to 2001-02), compared to the Bt cotton period of 2002-03 to 2010-11, per studies of A Narala and AR Reddy of the Central Institute of Cotton Research (CICR), Nagpur, in 2011, published when Kranthi was the Director of CICR. It is not expected that any one technology will contribute wholesomely to yield increase, and this is true of Bt technology.
India does not grow Bt cotton varieties, and hence, there is no area-wide data available to estimate the importance of Bt cotton without the hybrid vigour component. But its neighbour Pakistan grows only Bt cotton varieties, over about 30 lakh hectares, and has similar agro-climatic conditions as found in India.
S Mansoor and his colleagues, in a recent review, spoke of 2020’s reported net yield gain of Bt cotton of 33-37.5 per cent over non-Bt cotton and a significant reduction in pesticide applications in Bt cotton. Furthermore, the net profit in Bt cotton was higher than that in non-Bt cotton, despite higher expenditure on the former.
Cotton hybrids are superior to cotton varieties and have captured the imagination of farmers since 1970, when the first cotton hybrid (H-4) was commercialised in India. H Dong and his colleagues at the Shandong Academy of Agricultural Sciences, in 2004, showed a significant increase in yield in both non-Bt cotton hybrids and Bt cotton hybrids over their respective counterparts. Further, our perusal of All India Coordinated Cotton Improvement Project data for 2001 to 2011 showed higher yield potential of Bt cotton hybrids over the non-Bt control in all the three cotton growing regions.
India’s obsession with Bt cotton hybrids is blamed for its lower yields as compared to other nations, notably the US, Australia, Brazil and China. These expectations cannot be considered fair, as soil fertility and productivity differ, and so do weather, agri-technologies and production practices. Even these countries have reported declines in yields, and up to a three-fold variation amongst them due to inclement weather, while some of our States showed as much productivity as these countries at times.
The third misconception is that “the growth in yields has been affected because the introduction of even more advanced GM traits was stopped in the country from 2005”. This is contentious point, as farmers have time and again shown their willingness to proactively take up new technologies.
Belief in technology
The recent spurt in growing illegal Bt herbicide tolerant (HT) cotton in India, reported for the first time by SABC in September 2017, shows that farmers believe in technologies that help them reduce costs and increase productivity. And nearly 20 per cent of the cotton area — mostly of Bt cotton — was sown with illegal Bt HT cotton in Maharashtra and Telangana despite the heightened crackdown on suppliers. The commercialisation of Bollgard-III (in Australia) with three insect protective traits and Bollgard-II (in the US and Brazil) with two insect protective traits along with HT, shows farmers’ eagerness to use technology to sustain yields.
It is contended that Bt cotton’s primary impact on agriculture will be its role in making farming more capital intensive — rather than any enduring agronomic benefits. This conclusion does not compare with the capital intensiveness of non-Bt cotton that prevailed during the 1970-90s due to the bollworm attack which had led many farmers to commit suicide.
The era of Bt cotton over 2002-2018 is biphasic, the first phase of eight years up to 2010 showing significant increase in yield and the second, from 2011, showing yield stagnation, despite the sustained use of fertilisers, insecticides and other agri-inputs. The latter phase is an indication of fatigue of existing technologies.
The failure to bring in quantitatively proportionate yield increases to various farm inputs will often lead to contentious arguments of their importance. We must move on with the next phase of technology to improve cotton yields. As of now, correcting imbalances in the current agronomic practices and widespread application of micro-irrigation technologies will help to sustain and even increase yields.
Merely stating alternative sustainable strategies for cotton farmers will only confuse them. As more than 72 per cent of the cotton area belongs to Bt cotton, producing about 75 per cent of the total global output, biotechnology has a definite role to play in the future, too. Increasing the area under Bt cotton and its adoption to the extent of 90-95 per cent, with agronomic benefits, making India the largest producer of cotton in the world, can be best considered as the Bt technology led cotton sustainability that farmers have faith in.
The authors are with the South Asia Biotechnology Centre, New Delhi. Views are personal.