Davis, California
November 21, 2008
New flood-tolerant rice varieties,
developed by an international team of researchers, including
scientists at UC Davis,
UC Riverside and the
International Rice Research
Institute in the Philippines, have passed field tests and
are expected to soon be available to farmers in Bangladesh and
India.
Flooding in those countries annually reduces rice yield by up to
4 million tons -- enough rice to feed 30 million people.
The new flood-tolerant rice plants were developed by identifying
a single gene -- called Sub1A -- that is responsible for flood
tolerance in rice. Identification of the gene enabled the
institute's plant breeders to use "precision breeding" to create
the new rice varieties. The new plants are effectively identical
to popular, high-yielding rice varieties, except that they
recover after severe flooding to produce abundant yields of
high-quality grain.
The researchers anticipate that the flood-tolerant rice plants
will be available to farmers within the next two years. Because
the plants are the product of precision breeding, rather than
genetic modification, they are not subject to the same
regulatory testing that can delay release of genetically
modified crops for several years.
"The impact of these new varieties is evident for farm families
as well as at a national production level," said UC Davis rice
geneticist Pamela Ronald, following an early November tour with
her research colleagues of the flood-tolerant rice field trials
in Bangladesh.
"To be part of this project as it has moved from my lab in
California to rice fields in Asia has been inspiring, and the
project underscores the power of science to improve people's
lives," said Ronald, who led the effort to isolate the Sub1A
gene. Her laboratory also showed that the gene is switched on
when rice plants are submerged in water.
Collaborating with Ronald on the 13-year project were David
Mackill, senior rice breeder at the International Rice Research
Institute; Julia Bailey-Serres, a geneticist at UC Riverside;
Kenong Xu, a postdoctoral researcher in Ronald's laboratory; and
researchers at the Bangladesh Rice Research Institute and the
Central Rice Research Institute of India.
Once Sub1A varieties are officially released within the next two
years, the key will be dissemination to smallholder farmers in
flood-prone areas. The International Rice Research Institute is
leading this initiative through a grant from the Bill & Melinda
Gates Foundation and Japan's Ministry of Foreign Affairs.
The research that led to the isolation of the Sub1A gene was
funded by U.S. Department of Agriculture grants to Ronald,
Mackill and Bailey-Serres. The breeding work was funded by the
German Federal Ministry for Economic Cooperation and Development
and the USDA.
From
genes to farmers' fields: Waterproof rice set to make waves in
South Asia
Delhi, India
November 21, 2008
Source:
International Rice Research
Institute (IRRI)
"Waterproof'
versions of popular varieties of rice, which can withstand 2
weeks of complete submergence, have passed tests in farmers'
fields with flying colors. Several of these varieties are now
close to official release by national and state seed
certification agencies in Bangladesh and India, where farmers
suffer major crop losses because of flooding of up to 4 million
tons of rice per year. This is enough rice to feed 30 million
people.
The flood-tolerant versions of the "mega-varieties"
-high-yielding varieties popular with both farmers and consumers
that are grown over huge areas across Asia - are effectively
identical to their susceptible counterparts, but recover after
severe flooding to yield well.
A 1-9 November tour of research stations and farms in Bangladesh
(photo) and India led by David Mackill (8th from left, standing
on low cement wall), senior rice breeder at the International
Rice Research Institute (IRRI), marked the successful completion
of a project, From genes to farmers' fileds: enhancing and
stabilizing productivity of rice in submergence-prone
environments, funded for the past 5 years by the German Federal
Ministry for Economic Cooperation and Development (BMZ).
The new varieties were made
possible following the identification of a single gene that is
responsible for most of the submergence tolerance. Thirteen
years ago, Dr. Mackill, then at the University of California
(UC) at Davis, and Kenong Xu, his graduate student, pinpointed
the gene in a low-yielding traditional Indian rice variety known
to withstand flooding. Xu subsequently worked as a postdoctoral
fellow in the lab of Pamela Ronald (7th from left, standing on
low cement wall), a UC Davis professor, and they isolated the
specific gene -called Sub1A-and demonstrated that it confers
tolerance to normally intolerant rice plants. Dr. Ronald's team
showed that the gene is switched in when the plants are
submerged.
A geneticist from UC Riverside, Julia Bailey-Serres, is leading
the work to determine exactly how Sub1A confers flood tolerance.
"Sub1A effectively makes the plant dormant during submergence,
allowing it to conserve energy until the floodwaters reced,"
said Dr. Bailey-Serres.
Typically, rice plants will extend the length of their leaves
and stem in an attempt to escape submergence. The Sub1A gene is
an evolutionarily new gene in rice found in only a small
proportion of the rice varieties originating from eastern India
and Sri Lanka. The activation of this gene under submergence
counteracts the escape strategy.
"This project has been a great success, not only in its results
but also in the truly international collaboration that made the
project possible," said Dr. Mackill, referring to the several
national organizations, including the Bangladesh Rice Research
Institute (BRRI), India's Central Rice Research Institute and
Narendra Dev University of Agriculture and Technology.
"The potential for impact is huge," he said. "In Bangladesh, for
example, 20% of the rice land is flood prone and the country
typically suffers several major floods each year.
Submergence-tolerant varieties could make major inroads into
Bangladesh's annual rice shortfall and substantially reduce its
import needs."
Using modern techniques that allow breeders to do much of their
work in the lab rather than the field, Dr. Mackill and his team
at IRRI were able to precisely transfer Sub1A into high-yielding
varieties without affecting the characteristics-such as high
yield, good grain quality, and pest and disease resistance-that
made the varieties popular in the first place.
"The impact is evident for farm families as well as at a
national production level," said Dr. Ronald. "To be part of this
project as it has moved from a lab in California to rice fields
in Asia has been inspiring and underscores the power of science
to improve people's lives."
Because plants developed through this "precision breeding,"
known as marker-assisted selection, are not genetically modified
organisms (GMOs), the new Sub1 varieties are not subject to the
regulatory testing that can delay release of GMOs for several
years.
Once Sub1 varieties are officially released within the next 2
years, the key will be dissemination to smallholder farmers in
flood-prone areas. IRRI is leading this initiative through a
grant from the Bill & Melinda Gates Foundation and Japan's
Ministry of Foreign Affairs.
The International Rice Research Institute (IRRI) is the
world’s leading rice research and training center. Based in the
Philippines, with offices in 13 other countries, IRRI is an
autonomous, nonprofit institution focused on improving the
well-being of present and future generations of rice farmers and
consumers, particularly those with low incomes, while preserving
natural resources. IRRI is one of 15 centers funded through the
Consultative Group on International Agricultural Research
(CGIAR), an association of public and private donor agencies (www.cgiar.org).
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