BEIJING -?Chinese scientists have mapped the genome sequence of allopolyploid Brassica juncea, or mustard, a vegetable commonly used in Chinese cooking.

Zhejiang University's Zhang Mingfang, who is a member of the research program, said Tuesday that the sequencing would help scientists understand and improve the agriculturally important vegetable.

The research paper was published in the Nature Genetics journal.

Brassica juncea, known as "jei cai" in its native China, contains a diverse range of oilseed and vegetable corps important for human nutrition. It mainly grows south of the Yangtze River.
Zhang said under the program, the team has, for the first time, analyzed the cause of mustard's different genetic expressions.

He said mustard used for pickling and oil can bring great economic and social benefits. China has 133,000 hectares of mustard for pickling.

Pickled mustard uses a variant of Brassica juncea. Once processed, the stem retains its crisp texture.

Yang Jinghua, one of the authors of the paper, said scientists had previously published the genome maps of Chinese cabbage and kale. The genome of jei cai has more flexible phenotypes and a complex evolutionary process, which made it harder to decode, he said. The vegetable has double genomes after its natural hybridization between Chinese cabbage and black mustard.

For future application, Yang said they aim to develop a more hardy variant of the plant, which will result in larger yields.

"Some of the Brassica juncea are better at resisting disease, but others are the complete opposite. We can improve it through molecular breeding if we find the genes which determine the strength of disease resistance," he said.