Chinese scientists find gene that improves rice yields by 20 per cent

PUBLISHED : Friday, 22 May, 2015, 8:01am
UPDATED : Friday, 22 May, 2015, 8:01am

Chinese scientists have discovered a new “dwarf” gene in rice, which could increase the yield of the most productive hybrid rice in China by a further 20 per cent.

By reducing the rice plant’s height, the gene reduced the incidence of stem collapse prior to harvest and increased the number of tillers per plant, enabling a significant increase in grain yield.

The study, led by professor Wu Yuejin with the Chinese Academy of Sciences (CAS) Hefei Institute Physicial Science and professor Fu Xiangdong of the CAS Institute of Genetics and Development Biology, was detailed in the journal Plos One earlier this month.

To feed the world’s largest population, China launched an ambitious project to develop high-yielding “super rice” in the mid 1990s. Over time scientists had significantly improved the productivity of hybrid rice, and by last year the yield of “super rice” plants had exceeded 15 tons per hectare, nearly three times the global average.

But the yield increase came with a problem. Farmers complained that the super rice plants, with their heavy heads of grains, were prone to snapping, especially in windy days before harvest.

A lot of research worldwide has gone into trying to find sturdy stems. Wu and Fu’s team chose to bombard rice seeds with heavy ions and after some years found that some seeds mutated to produce plants with reduced heights and an increased number of tillers.

The scientists identified the mutant gene and called it sdt, meaning “semi-dwarf and high-tillering”.

Further experiments confirmed the discovery and then the gene was cloned onto super rice, resulting in reduced plant heights and an increase in yield of over 20 per cent.

Though the super rice was more productive than traditional hybrid rice, “the continuing growth of the world’s population and the limited arable land resources require that grain yield capability of rice will have to be raised yet further,” the researchers said in their paper.

The sdt mutant “will be useful for farmers and breeders to improve grain yield potential of rice over what is currently available.”