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Wednesday, May 18, 2022

Genetically modified crops: Taking fear-mongering to new heights

Concerns over GM mustard impacting pollination and honey production have no empirical basis

Written by Govind Gujar, Bhagirath Choudhary |
Updated: June 8, 2017 9:44:35 am
Genetically Modified Crops, GM Mustard Deepak Pental (second from left) with fellow scientists from the Centre for Genetic Manipulation of Crop Plants in Delhi University at a mustard trial field. (Express photo: Oinam Anand)

Pollinators such as honeybees play a vital role in our agricultural production systems. Roughly a quarter of the world’s food is estimated to come from transfer of pollen, from the male to female organs of the flowers of plants, by bees. India alone is home to four major species of honeybees – Apis mellifera (European bee), Apis cerana indica (Indian bee), Apis florea (dwarf floral) and Apis dorsata (rock bee) – of which the two have been domesticated, whereas the others are wildly-occurring and found mainly in forests. The domesticated bees are maintained in manmade hives not only for production of honey, wax and other by-products; beekeepers sell honeybees from their colonies also to other farmers for improving crop pollination and resultant yields.

Unfortunately, honeybees are in the news today for an entirely different reason related to unsubstantiated fear-mongering by so-called environmentalists and NGOs claiming to speak for farmers. Cultivation of genetically modified (GM) mustard now awaiting regulatory clearance, it is alleged, will cause a 30-40 per cent reduction in production of nectar in flowers, thereby attracting fewer bees to collect and make honey from it. The end-result: lower production as well as export of honey from India!

We have heard such wild theories before; they surface whenever any new GM crop is ready for environmental release. Take Bt cotton. At the time of its commercial approval in 2002, many anti-GM activists claimed that the widespread cultivation of cotton hybrids containing gene(s) derived from the Bacillus thuringiensis soil bacterium would hugely reduce pollinator populations. Well, farmers did resort to widespread cultivation of Bt cotton, which, in 2016-17, covered 10.6 million hectares or 95 per cent of the country’s total area under the crop. But this caused no harm to either bee activity or honey production.

A recent study by entomologists at the University of Agricultural Sciences, Dharwad (Karnataka), investigating the impact of Bt cotton on pollinator fauna and honeybees, showed no hindrance to their foraging activity. The study even suggested relative abundance of natural insect predators in cotton fields, which may have had to do with the overall reduced insecticide sprays courtesy Bt technology. In fact, the higher yields from Bt cotton are themselves a result of conservation of pollinators and more number of honeybee colonies.

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Against this background, it is surprising to see the same stories of “threat” to the beekeeping industry being repeated in GM mustard, which has been recommended for commercial planting by the Genetic Engineering Appraisal Committee (GEAC) in the Union Environment Ministry. In Bt cotton, it could be said, for argument’s sake, that the alien genes introduced into the crop codes for a protein toxic to insects – even if specific to the heliothis species, particularly the dreaded American bollworm. But in GM mustard, even that logic does not hold.

The GM mustard, developed by Deepak Pental and fellow scientists at the Centre for Genetic Manipulation of Crop Plants in Delhi University, contains no insecticidal protein gene. It has mainly two genes (‘barnase’ and ‘barstar’) that allow for cross-pollination and hybridisation in mustard, which is largely a self-pollinating plant because of its individual flowers containing both female and male reproductive organs. In addition, there is a third ‘bar’ gene, conferring tolerance to the herbicide glufosinate. This is basically a marker gene, used to identify those plants that have been genetically modified – the non-GM plants cannot withstand glufosinate application – and are necessary for large-scale hybrid seed production.

Now, it should be obvious that a crop expressing hybrid vigour – GM mustard has been shown to yield 20-30 per cent more than the existing popular ‘check’ varieties – will have more flowers per plant. Wouldn’t that attract more rather than less honeybees and other pollinator insects? The Assessment of Food and Environmental Safety report, prepared by a sub-committee of scientific experts constituted by the GEAC, has clearly established no difference in honeybee foraging behaviour between GM and non-GM mustard. This was based on field studies in six locations over three seasons (2010-11, 2011-12 and 2014-15) as part of biosafety research level (BRL-1 and BRL-2) trials conducted by Indian Council of Agricultural Research and state agricultural universities. Biosafety studies, moreover, concluded that the ‘barnase’ and ‘barstar’ proteins weren’t detectable in the GM mustard pollens, hence ruling out any exposure – even if not harmful – to honeybees.

As far as the ‘bar’ gene goes, the presence of its proteins at very low levels in the pollen has not revealed any adverse effect on bee foraging, colony health or the quality of honey produced. The ‘bar’ protein, produced in glufosinate-tolerant GM crops, has received regulatory approval in as many as 20 different countries (including in the European Union), as per a 2016 International Life Sciences Institute study. Glufosinate spraying, as already noted, is required only for seed production. Even assuming farmers apply this herbicide, they would do so only during the first fortnight after germination or, at the most, within a month after sowing. Flowering in mustard happens only after 45 days, when there’s no threat from weeds and no necessity for herbicide application. How can, then, glufosinate spraying impact honeybee visits during pollination? On the contrary, removal of weeds will boost plant growth and make it flower more, which would attract larger bee populations.

If at all anybody is aware about the role of honeybees with respect to mustard, it’s the breeders themselves. Honeybees are known to visit the crop during flowering to enhance pollination. Studies carried out at the Indian Agricultural Research Institute, New Delhi have demonstrated that the exclusion of honeybees can significantly bring down yields in mustard, despite it being a self-pollinated plant. Another study at the GB Pant University of Agriculture and Technology in Uttarakhand has found as many as 18 different insect pollinators visiting mustard. Our scientists should be credited with at least minimum intelligence; no breeding programme in mustard will pass muster without factoring in the predominant role of honeybees in enhancing seed setting necessary for higher yields!

In conclusion, the concerns over GM mustard “contaminating” our honey and compromising the livelihoods of beekeepers are sheer figments of imagination. GM mustard is no different from GM canola, which is also a brassica genus plant and whose oil is already being imported into India. When no adverse impact on pollinators, bees and honey production has been reported by GM canola-growing countries, including Australia, Canada and the US, in the last 20 years, why should different standards apply to GM mustard that Indian farmers will hopefully plant soon?

Govind Gujar is former head of the Indian Agricultural Research Institute’s Division of Entomology and Bhagirath Choudhary is with the South Asia Biotechnology Centre, New Delhi

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