Chinese scientists have successfully identified a rice gene that controls a grain's weight and are experimenting with the new discovery to boost grain yield.

The previously unknown gene, called GW2, is responsible for limiting a grain's size and weight, said scientists with the National Key Laboratory of Plant Molecular Genetics in Shanghai.

Lin Hongxuan, one of the researchers, said a weaker dominance of the gene could speed up the splitting of grain cells and enlarge the size, which would lead to higher weight and output.

Scientists have picked out the gene in existing large-grain varieties in which the GW2 gene is relatively recessive and introduced it into small-grain varieties.

This led to new varieties from grains larger than the original. Though each rice spike contained less grains as they grew larger and heavier, the overall weight still increased markedly.

It would be certainly valuable for improving grain yield, but it was too early to predict how it would enhance the rice output if applied in paddy field.

Their research results have been published on the website of Nature Genetics, whose judges described it as a landmark discovery in rice cultivation.

Earlier reports said the research team of Lin, Song Xianjun and Huang Wei had also identified the gene controlling the grain's quantity.

They were also working on that gene in the hope of controlling both quantity and quality and producing varieties with higher yields.

(Xinhua News Agency April 13, 2007)