BEIJING -- Humans started to domesticate cereals about 10,000 years ago, producing more grains to support larger populations. Now, a Chinese study has revealed the genetic basis of the yield increases in maize and rice, two important sources of human calories.

Scientists from China Agricultural University and Huazhong Agricultural University identified a gene called KRN2 that differs between domesticated maize and its wild ancestor, teosinte.

This gene put a cap on the kernel row number in maize, but human selection suppressed its expression and resulted in an increased grain number through an increase in kernel rows, according to the study published on Friday in the journal Science.

The researchers subsequently found that a gene in rice called OsKRN2 shows a similar pathway, according to the study.

The field tests showed that the suppression of those two genes in maize and rice increased grain yield by about 10 percent and 8 percent, respectively, with no apparent trade-off in other agronomic traits.

Li Jiansheng, the paper's co-corresponding author and CAU professor of plant genetics and breeding, said the discovery of key genes related to yields laid the foundation for breeding better seeds and safeguarding China's food safety.