Goodness of rice locked in genetic history

January 24th, 2009 - 3:54 pm ICT by IANS  

Washington, Jan 24 (IANS) Researchers have isolated a gene that could help develop superior rice strains requiring less space, water and maintenance to feed more and more hungry people across the world. Scott A. Jackson, professor of agronomy, Purdue University, who was associated with the study, said that “we need to grow more food to feed the human population, and it needs to be done on less land and with less water”.

Understanding the variations could allow scientists to place genes from wild rice species into domesticated ones to create varieties with more branching, increased plant size or other favourable characteristics.

By comparing the domesticated plant to other wild rice species, they discovered a lot of genetic variation in rice over millions of years, Jackson said.

Jackson worked with Rod A. Wing of the University of Arizona and Mingsheng Chen of the Chinese Academy of Sciences in Beijing, co-authors of the study.

The research team developed a tool to compare genes in different species of Oryza, of which domesticated rice is a species. Jackson said the comparisons showed how rice has changed from as far back as 14 million years ago.

As rice adapted to climate changes and other natural circumstances, its genetic structure changed, keeping some genes and losing others.

About 10,000 years ago, humans began making their own genetic modifications, albeit unknowingly, by choosing plants that had favourable traits. As they stopped growing plants with unfavourable characteristics, genes responsible for those traits disappeared.

“Humans knew that if the seeds stayed on the plant, or it had a higher yield, they could save some of the seeds to plant next year,” Jackson said. “That was unintentional breeding.”

Those favourable genes are still around in wild rice species because they were valuable for plants in other climates or situations, he said.

One example can be found in a variety of rice that has genes making it drought-resistant. Scientists could breed those genes into domesticated rice in Africa where water shortages can devastate crops, said a Purdue release.

These findings were published in the Proceedings of the National Academy of Sciences online version this week.

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