Hybrid rice developed by Chinese scientist Yuan Longping and his team achieved record-breaking yields of 1,500 kilograms per mu (about 22.5 tonnes per hectare) in two growing seasons, according to the assessment results from a test field on Monday.     

The late-season hybrid rice yield in a field in Central China's Hunan Province reached 911.7 kilograms per mu – each mu is about 0.07 hectares.

"I would be very happy if it exceeds 880 kg (per mu). Now it exceeded 900 kg (per mu), I am extremely happy," Yuan Longping, the 90-year-old agricultural expert dubbed the "father of hybrid rice," said after the yield was announced on Monday. 

In July, another strain of early-season crops in the same field achieved a yield of 619.06 kg per mu. The combined output of the two seasons in a year sets a new world record for rice yields.  

Hunan is a major rice producer in China, where farmers plant double-cropping rice. 

"High yield and resistance to disease, cold and lodging are the advantages of the third generation hybrid rice, compared with the previous two generations," said Li Xinqi, a researcher at Hunan Hybrid Rice Research Center and host of the third-generation hybrid rice project. 

High yield achieved under unfavorable conditions

This year's high rice yields occurred under unfavorable conditions, such as low temperature and shorter durations of sunlight, Li Xinqi said. 

Li Qiusheng, an agronomist with the agriculture and rural affairs bureau in Hengnan County, said according to meteorological data during the critical period of rice growth, 43.85 effective sunshine hours were recorded this year, compared to 187.8 last year. 

"The village was not particularly chosen for the test of the new generation hybrid rice. Besides, the rice did not receive any special care, which is not much different from normal farming by ordinary farmers," Li Qiusheng said. 

Under similar conditions, local double-cropping rice yields averaged between 700 kg and 800 kg per mu, while the new hybrid rice exceeded 1,500 kg per mu. 

Li Jianwu, an expert with the Hunan Hybrid Rice Research Center, said the expert team had visited the test fields only twice from sowing to harvesting, which differs from the long-term guidance rendered to rice farmers in the past.

Contributing to food security

China now feeds around 20 percent of the world's population despite having less than 9 percent of the world's arable land. 

Yuan, who developed the world's first hybrid rice in the 1970s, has set multiple world records in hybrid rice yields in previous years, making great contributions to food security in China and the world. 

Yuan's team is still working on the third-generation hybrid rice combinations and conducting studies for the simplified cultivation of the rice, aiming at high yields with less use of fertilizers. 

Yuan said he wants to ensure the third-generation hybrid rice variety boasts "the comprehensive strength to promote a greener and more sustainable development of China's rice production with higher quality and yield." 

(With input from Xinhua)