by Piyaporn Hawiset
22 October 1999
New strains of artificially selected, drought-resistant rice could help improve the water efficiency in rice-growing regions of the world, according to scientists at the International Rice Research Institute (IRRI) in the Philippines.
At present, rice is the staple diet for 2.9 billion people--around half the world's population. In Asia, where 90 percent of all rice is grown and the vast majority of it consumed, 72 percent of fresh water resources are used for irrigating rice crops. However, water availability has been shrinking as domestic and industrial demand has increased.
Although it is widely acknowledged that more could be achieved by improving irrigation strategies in areas with unreliable rainfall such as the eastern sialnds of Indonesia, the development of drought-busting rice plants is an important alternative as 45 percent of rice growing areas in Asia still lack proper irrigation infrastructure.
With the help of a genetic data-base listing over 80,000 known varieties of rice, IRRI researchers have been homing in on the genes for drought-resistance.
Using a technique called marker assisted selection, the process of cross-breeding for desired traits is being speeded up in comparison with traditional methods. Marker assisted selection does not modify a plant's genetics, but it identifies individual plants with the required genes. Desired traits include deeper and thicker growing roots, and the ability to take up nutrients when growing in relatively dry soil.
Dr. Adam Price of the Department of Plant and Soil Sciences at Aberdeen University in the United Kingdom, said, "It is important to understand that there is no way to find a single gene on one of the 12 rice plant chromosomes which will lead to a universal drought-resistance. And selecting for particular chromosomes or genes is an expensive process."
Dr. Price's team has ben using marker assisted selection to breed a popular variety of Indian rice for seep-rooted and aromatic habit. He said, "We are still in the early stages, but subject to success, Kalinga III could be ready for use by Indian farmers by 2001 or 2002."
When asked whether a particular strain could be patented, Dr. Price said, "Rice is unusual, because so far it has not really been a commerical crop in the sense that farmers do not have to buy in large quantities of seed. Once farmers have the seed, it is a relatively simple matter for them to breed the plants on site. However, although export markets for rice are not that important, I do expect this [patent rights] to be an increasingly important area."
Advances in the ability of popular rice strains to withstand drought could have a significant effect on agricultural efficiency. However, the rate at which research is translated into action will be limited by the availability of suitably equipped laboratories and agricultural universities, which can breed up the new strains for distribution to farmers.
Dr. Mahabub Hossain, IRRI's chief economist estimates that 24 million tonnes of rice--worth $4.8 million to the Asian economy--is lost each year, as a direct result of drought.