Genetic diversity and association mapping of cadmium tolerance in bermudagrass [ Cynodon dactylon (L.) Pers.]

Background and aims Identification of the association between Cd tolerance-related traits and molecular markers facilitates an efficient selection of the tolerant cultivars. The objectives of this study were to analyze the Cd tolerance and the genetic diversity of native bermudagrass accessions in China, and to identify marker-trait association with wild bermudagrass. Methods A countrywide collection of 120 bermudagrass [ Cynodon dactylon (L.) Pers.] accessions were evaluated for Cd tolerance and genetic diversity with simple sequence repeat (SSR) markers. Result Significant variations in 7 physiological parameters were observed among the accessions under Cd conditions. The 104 SSR primers amplified 1474 alleles. The average gene diversity and polymorphic information content (PIC) for the whole sample was 0.2270 and 0.1894, respectively. Clustering analysis showed that the distance of genetic relationship was affected by the cultivars of natural habitats and the edaphic conditions. Thirty one SSR markers were associated with more than one trait ( P < 0.01), while 37 markers were identified by corrected P values ( P < 3.5 × 10 −4 ). Conclusion Thirty one SSR markers were associated with a reduction in 7 traits under Cd stress. These markers can be used for genetic improvement of Cd tolerance of bermudagrass after further validation.