SHIJIAZHUANG, Oct. 29 -- Chinese scientists have finished the genome sequencing of the Chinese jujube tree, providing an insight to develop better quality jujube fruits.

Jujube trees are indigenous to China with 99 percent of the world's jujube plantations in China. The plant is the source of income for more than 20 million Chinese farmers.

The genetic research was carried out by professor Liu Mengjun and his research team in the Hebei Agricultural University since 2010. It has led to finding special genes that enable the plant to resist drought, high salt in the soil and give it high sugar content in its fruit.

According to research of the plant's fossils and cultural relics, humans started using jujubes around 7,000 years ago. Jujube trees have since been introduced to 40 countries.

Jujube trees tolerate a wide range of temperatures, able to survive winters as cold as minus 15 degrees Celsius, which makes it a good fruit tree to grow in mountains and desert regions. Chinese traditionally eat dried jujube fruits or red dates as a nutritious snack.

Liu said research teams used ziziphus jujube trees, or winter jujube, to sequence 438 megabases of the jujube genome, and annotated more than 32,000 jujube genes.

He said the genetic mapping program has led China's research in fruit tree genomics to the first class level internationally.