Climate change has reduced by 15 per cent the yield of the “miracle rice” which helped avert famine in Asia in the 1960s, the International Rice Research Institute said on Friday.

A study conducted by the Manila-based institute showed that the yield of the IR8 rice variety, also known as “miracle rice,” had dropped to 7 tons per hectare from yields of 9.5 to 10.5 tons per hectare when it was first introduced.

Before the introduction of the new rice in the 1960s, the average global rice yield per hectare was only around 2 tons.

“Our study eliminated changes in the genetic composition of the IR8 which may have occurred over time, and instead identified changes in the environment as the cause of the decline,” Shaobing Peng, a crop physiologist from the institute, said.

“Hotter nights, which are known to reduce rice yields, and other environmental changes such as modification in soil properties ... and air pollution are all possible contributing factors,” Peng added.

He said their study underscored the need for further breeding to make future generations of rice plants better able to cope with a changing environment.

“Maintenance breeding needs continuous support to help farmers to cope with erratic climate changes around the globe,” Peng said.