Genetic diversity and relationships among cabbage (Brassica oleracea var. capitata) landraces in China revealed by AFLP markers
Genetic diversity and relationships among Chinese traditional cabbage landraces have not yet been well investigated. To explore the diversity, 83 landraces originating in Northern China, Southern China, Eastern Europe, Western Europe as well as other countries were evaluated by using AFLP markers. Results indicated that cabbage landraces exhibited a relatively low level of diversity. Among the 575 markers, 41.9% were polymorphic with an average PIC value of 0.354. Unweighted pair group method with arithmetic averages (UPGMA) cluster and population structure analysis consistently divided all landraces into two major groups reflecting geographic origins. Group 1 was a distinct group comprised of Northern China landraces and Eastern European landraces, whereas Group 2 was comprised of populations of Southern China landraces, Western European populations and other countries. Landraces with varied maturing times or head types could not be distinguished based on molecular data. The Northern China population was closely allied to the Eastern Europe population (D = 0.037). The integration of our data with historical documents confirmed that traditional cabbage landraces cultivated in North of China were first introduced from Russia.
Key words: Amplified fragment length polymorphism (AFLP), genetic diversity, cabbage (Brassica oleracea var. capitata), landraces, population structure.