By Jacob P. Koshy
Rice, which is staple food for nearly half the world?s population, is
also a major water-guzzler. It typically uses two-three times more water
than, say, an equivalent quantity of wheat or maize. Now, according to a
group of scientists, inserting a particular gene may improve rice?s
water-use efficiency by at least 20%.
The ?hrd-D?, a mutant gene, that?s been identified in a tropical weed
called Arabidopsis, has been known to strengthen root systems, help plants
better tolerate drought- and excess salt-conditions?typical traits of plants
that grow in arid climate. But a scientist couple?Aarati and Nataraja
Karaba, at the University of Agricultural Sciences, Bangalore, found that
incorporating this gene into rice, at a particular location in its genome,
significantly improved its drought-tolerance capacity.



Reporting their findings in the peer-reviewed Proceedings of the
National Academy of Sciences, Nataraja said the rice plant with the inserted
gene had greener leaves, and thus better photosynthetic capacity, without
any reduction in its growth or yield.



?So, if you use a litre of water to produce a given amount of rice,
our experiments show that inserting this gene gives the same quantity of
rice, by using 700-800ml,? he added.

What this means for a water-starved India is significant. Water
scientist and adviser to the World Wildlife Fund Biksham Gujja, said:
?Freshwater is a precious resource in India and rice production typically
consumes 30% of the available freshwater. Given that over 90% of India
depends on rice, economical management of freshwater is a must.?



The scientists are part of a research team in the Wageningen Research
Centre, the Netherlands, headed by Andy Pereira, which has sequenced the
Arabidopsis genome. ?We have access to the genome and our job was
essentially playing around with the Arabidopsis genes. We are trying out
various genes, and inserting them into crops of interest to us,? said
Nataraja, who specifically studies the drought tolerance aspect in crops,
and itries to dentify genes that could help crops such as rice, wheat and
maize.



A lot of tests remain to be done. ?This is an encouraging step, but we
need to try this gene out with rice varieties specific to India, and
practical results can be got onlyfrom field trials,? cautioned Nataraja.
Genetically-modified food crops are yet to be allowed in India, and the only
genetically-modified rice varieties that are in preliminary stages of
trials, are being tested for pest resistance.



A lot, however, depends on the success of genetically-engineered
Indian variety of ?golden rice?, which is still in preliminary stages of
trials. ?Golden rice? is a Swiss-developed genetically engineered strain of
rice that?s high on Vitamin-A, though its possible entry into farmer fields
has drawn ire from organizations such as Greenpeace in India.

However, the Karabas? research finding has evoked interest in the
scientific community here. ?It?s an interesting finding,? said A.K. Singh,
head of the water management division with the Indian Agricultural Research
Institute, ?but even we are developing rice varieties that use 40% less
water, though they come with the caveat of strict fertilizer and sowing
inputs.


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