The information derived from rice will contribute to the study of other important cereals such as wheat and corn

Dr David Evans, Syngenta

Syngenta and Myriad Genetics Inc say that knowing the complete set of biochemical instructions required to build the plant will enable the development of new strains with greater yields and better tolerance of harsh conditions.

The completed DNA sequence, of the variety Nippon-Bare, will not be published in a scientific journal or on the internet but will be made freely available to scientists who want to use it.

Dr Steve Briggs, of the Torrey Mesa Research Institute in California, US, where much of the decoding work was carried out, said: "We expect plant breeders who use this information to have an impact on new varieties in the next five years."

Major merger

Syngenta was formed last year by merging the agribusiness activities of Novartis and AstraZeneca. It is now the world's largest crop protection company and number three in the market for developing important commercial seeds.

A rice has been engineered to produce beta-carotene, a precursor our bodies need to make vitamin-A

Its rice genome programme began in 1999 and was an initiative that ran in parallel with academic efforts.

The rice genome is spread across 12 chromosomes. It is made up of 430 million bases of DNA, representing approximately 50,000 genes, making it the second largest genome of any kind to have been sequenced to date.

"The rice genome is full of surprises and possibilities," Dr Steve Briggs told BBC News Online. "We still do not know what 20% of the genes do. Some of the rice genes are shared with other plants, some are unique.

"But the biggest surprise is that the overall gene architecture and sequence is nearly identical to that of cereals. This means we truly have a plant genetic blueprint."

The decoding of the genome is expected to provide the basic information required to engineer new types of rice with novel traits. It will also lead to the development of new pesticides aimed at specific pests.

'Golden rice'

Genetics has already produced a "golden rice" variety which has been engineered to produce beta-carotene, a precursor our bodies need to make vitamin-A.

The first, completed genome of a plant, Arabidopsis thaliana, was published last year

Normal rice has no beta-carotene and this has led to health problems in millions of people who rely on the plant as a staple food.

Dr David Evans, head of Syngenta's research and technology division, said: "Because of the similarity between different cereal crop plants, the information derived from rice will contribute to the study of other important cereals such as wheat and corn."

The international development agency ActionAid cautioned that novel plants produced with the new technology should not leave poor farmers in the developing world in the grip of big business.

"Syngenta must commit to sharing this work with developing countries' researchers and should not patent genes and DNA from this or any other plant genome," ActionAid campaigner Alex Wijertana said.

The first plant to be decoded was a small weed, Arabidopsis thaliana. It has a much smaller genome with just 26,000 genes.