Business Standard

Tuesday, August 26, 2003

FARM VIEW

Cottoning on to Bt

Scientists are offering suggestions to harness the true potential of this
hybrid, says Surinder Sud

Environmental activists might have passed a verdict on transgenic,
insect-protected Bt cotton hybrids, holding them unworthy of cultivation,
but there is no final word on them yet from state governments, public sector
cotton scientists and, most importantly, farmers.

The last kharif was the first year of commercial cultivation of these
genetically-modified (GM) cotton plants on farmers' fields in six states.
The reports on the performance of Bt cotton sent to the Centre by these
states do not really confirm whether they are good or bad.

Scientists of the Nagpur-based Central Institute of Cotton Research(CICR),
who closely monitored these hybrids, are also non-committal.

But what is of significance is that none of them have rejected this
technology - instead, they have offered useful suggestions for modifying it
to harness its commercial potential.

Transgenic Bt cotton hybrids have a gene of non-plant origin borrowed from a
soil bacteria called Bacillus thuringiensis (Bt). This gene, called the Cry
1 Ac gene, helps produce a toxin in the cotton plant that kills bollworms.
Thus, Bt cotton is supposed to protect the crop against American bollworm
(Heliothis) which has emerged as the biggest enemy of cotton.

Three transgenic Bt cotton hybrids (MECH-12, MECH-162 and MECH-184) produced
by Mahyco-Monsanto Co were given conditional approval on March 26, 2002, for
cultivation in six states - Gujarat, Maharashtra, Andhra Pradesh, Karnataka,
Tamil Nadu and Madhya Pradesh.

Barring Gujarat, all other states have stated that the incidence of bollworm
was lower on Bt cotton compared to non-Bt hybrids. Some of them also stated
that the number of times pesticides were sprayed was nearly half in the case
of Bt cotton.

The CICR held that Bt hybrids performed much better than the local hybrids
on about 80 per cent of the area, indicating the efficiency of this new
technology though, in certain pockets, plants wilted owing to adverse
climatic factors.

Gujarat was the only state to have reported that the MECH-162 hybrid was
found vulnerable to bollworm and that MECH-12 was susceptible to sucking
pests. All states also pointed out certain other problems that need to be
addressed.

For instance, Madhya Pradesh said the approved hybrids were not suitable for
light soils; they needed heavy soil with good drainage. Maharashtra
discovered that though the performance of Bt cotton hybrids was better
compared to that of their non-Bt counterparts (the same hybrid minus the
Bt-gene), it was not so against other popular non-Bt cotton hybrids.

Agro-climatically, last year was not an ideal period to assess the true
worth of the Bt cotton given the drought. Both pest incidence and crop yield
were low due to the dry weather.

Besides, the total area planted with these hybrids, estimated at a mere 0.5
per cent of the total cotton acreage, was too small to make a valid
evaluation of the technology.

However, some of the technical issues raised by the CICR merit serious
attention by policy planners as well as corporate houses engaged in the
research and commercial promotion of transgenic cottons.

For instance, the CICR has discovered that the duration of the Bt gene
expression (that is, the presence of the insect-killer protein in plants) is
small and needed to be enhanced by 20 to 30 days to protect the plants from
bollworm damage in the later part of the season.

CICR has also sought to address the apprehensions expressed by most
detractors of this technology that prolonged use of Bt cotton hybrids would
lead to the development of resistance to Cry 1 Ac gene in bollworms.

To overcome this hypothetical problem, the CICR has suggested that "gene
stacking" (putting more than one gene into the plant) should be considered
seriously. The technology to do so already exists.

Indeed, the basic advice that the cotton scientists have to offer to improve
the commercial potential of this technology is that the parental lines (the
Bt gene recipient hybrids) should be selected more carefully with an eye to
actual field conditions obtaining in the particular cotton belt.

For the country's major central cotton bowl, for example, the Bt gene needs
to be incorporated in those plants that are hardy enough to withstand
stresses, including attack by sucking pests prevalent in this region.

Basically it means that the choice of MECH-12 for Bt-gene incorporation was
flawed though this hybrid scores in terms of quality of cotton and the
yield.

Perhaps the private sector Bt cotton producers will become more careful once
public sector Bt cottons are available to compete with their products.

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