In one of the largest human feeding trials of a staple food, 300 nuns in the capital Manila will be enlisted next year to help test a rice variety rich in iron and zinc that may help combat anaemia.

The IRRI is also helping develop genetically-modified rice known as "golden rice", aimed at combating Vitamin A deficiency, responsible for half a million cases of irreversible blindness and up to a million deaths a year among the world's poorest people.

"We are not only developing higher yielding rice but also developing super-value rice," 36-year-old Filipino scientist Glenn Gregorio of the IRRI told Reuters by telephone.

The Institute estimates that about one third of the world's population suffers from anaemia, which impairs immunity and reduces physical and mental capacity.

About 60 percent of all pregnant women in Asia and about 40 percent of school children are iron deficient.

GOLDEN RICE

The IRRI, credited widely for helping the world feed itself by developing high-yielding rice during the so-called Green Revolution of the 1960s, is one of several organisations around the world carrying out systematic work on improving crops.

Rice feeds about half of the world's population, and 90 percent of the total annual harvest comes from Asia.

Not all research into new crop varieties involves genetic engineering, but the IRRI is helping with work on genetically-modified Vitamin A enriched rice, or "Golden Rice".

This rice was developed by German scientists by implanting two genes from a daffodil and one from a bacterium into a japonica rice variety called T309. Samples of the grain were donated to IRRI this year for research and breeding.

IRRI's chief plant biotechnologist, Swapan Datta, believes genetic engineering could speed the quest for healthier rice.

"If there is a need and there is a possibility to have a new technology and new ways to improve nutrition, we should be doing that," he said.

Datta said the planting material for golden rice would be ready within two to three years. "Farmers can have them in five years. That's our hope," he said.

NUNS EXPERIMENT

In a bid to improve the nutritional value of rice, the IRRI's Gregorio is developing a new rice variety which it stumbled upon while working on research into rice with tolerance to low temperatures.

The variety, rich in iron and zinc and known as IR68144, was developed by cross breeding two varieties. It will be fed to nuns from eight Manila convents early next year, Gregorio said.

The IRRI, based near Manila, said the trial aims to convince nutritionists that the iron and zinc-enriched rice is capable of reducing the incidence of iron-deficiency anaemia.

The trial was originally set to begin this April, but delayed because of an inadequate harvest of the iron-rich rice.

"Typhoons late last year swamped our farm, resulting in a poor harvest," said Gregorio.

The IRRI said it had recently harvested enough rice in a nearly 13 hectare (32 acres) farm inside the institute to feed the sisters over a period of seven to nine months in the test which will be supervised by Cornell University and Pennsylvania State University in the United States.

"We tested 27 religious sisters in 1999," Gregorio said, adding that the iron status of the nuns improved after eating the rice exclusively for a period of six months.

"But nutritionists remained unconvinced, and that trial is now being regarded as a dress rehearsal for the main event," the IRRI said in its recent annual report.

In the new trial, about half of the 300 sisters will be fed with IR68144 and the rest will eat normal rice for up to nine months.