Recently, the international academic journal Nature published online the research results led by Duan Qiaohong, a professor of Shandong Agricultural University. This study revealed the molecular mechanism of Chinese cabbage and other cruciferous vegetables maintaining interspecific reproductive isolation by regulating the level of reactive oxygen species in the stigma, and developed the breeding technology to break the reproductive isolation of distant hybridization, successfully obtained the interspecific and intergeneric distant hybridization embryos of Chinese cabbage, opened up new ideas and new ways of distant hybridization breeding, and made Chinese cabbage obtain the freedom of "mate selection". Cruciferae vegetables are the most widely cultivated and edible vegetables in China, and the planting area accounts for about 25% of the total vegetable area. Common vegetables on the table, such as Chinese cabbage, cabbage, mustard, radish, all belong to the family Cruciferae. Cultivating more high-quality varieties of cruciferous vegetables is of great significance to the stability of the "vegetable basket". Distant hybridization breeding is an important way of germplasm innovation, which can effectively expand the genetic range of germplasm resources. Due to long-term survival and evolution in the wild, wild species have excellent genetic resources such as disease resistance, insect resistance and stress resistance. It can effectively improve the resistance of vegetables to diseases and pests by introducing it into the genome of vegetable cultivars through distant hybridization. However, reproductive isolation seriously hinders the application of this technology. The traditional distant hybridization breeding mainly selects the hybrid parents through extensive test crossing, which is laborious, laborious and extremely inefficient, even zero. "If you want to make full use of the high-quality gene resources of distant species, first of all, you need to systematically analyze its regulatory mechanism." Duan Qiaohong introduced that the team found that the high level of reactive oxygen species on the pistil stigma is the key factor of reproductive isolation. Distant pollen stimulates the increase of reactive oxygen species in stigma, or prevents the decrease of reactive oxygen species, and inhibits the growth of distant pollen, thus preventing gene flow among species. "Through the breeding technology that we developed to remove the stigma reactive oxygen species to break the barrier of distant hybridization of cruciferous vegetables, we successfully obtained the interspecific and intergeneric hybrid embryos of Chinese cabbage, laying a solid foundation for the subsequent creation of breakthrough new germplasm." Yang Lin, a doctoral student, said that at present this breeding technology is being applied to the breeding of cruciferous vegetables. Huang Sanwen, president of the Chinese Academy of Tropical Agricultural Sciences, said that the research will introduce the excellent gene resources of distant species into cultivation through new technologies, broaden the genetic range of germplasm, greatly promote the development and utilization of excellent gene resources of distant species of Cruciferae, and lay a solid foundation for the creation of breakthrough germplasm and the cultivation of new varieties. This study also provides new ideas for the utilization of wild resources of other crops. (Outlook New Era)