Bermudagrass (Cynodon dactylon Pers.) is an important warm-season perennial used extensively for turf, forage, soil conservation and remediation worldwide. However, limited genomic information has hindered the application of molecular tools towards understanding genome evolution and in breeding new cultivars. We genotype a first-generation selfed population derived from the tetraploid (4x = 36) ‘A12359’ using genotyping-by-sequencing. A high-density genetic map of 18 linkage groups (LGs) is constructed with 3,544 markers. Comparative genomic analyses reveal that each of nine homeologous LG pairs of C. dactylon corresponds to one of the first nine chromosomes of Oropetium thomaeum. Two nested paleo-ancestor chromosome fusions (ρ6-ρ9-ρ6, ρ2-ρ10-ρ2) may have resulted in a 12-to-10 chromosome reduction. A segmental dissemination of the paleo-chromosome ρ12 (ρ1-ρ12-ρ1, ρ6-ρ12-ρ6) leads to the 10-to-9 chromosome reduction in C. dactylon genome. The genetic map will assist in an ongoing whole genome sequence assembly and facilitate marker-assisted selection (MAS) in developing new cultivars.

百慕大草（Cynodon dactylon Pers。）是重要的暖季多年生植物，广泛用于全世界的草皮，牧草，土壤保持和修复。然而，有限的基因组信息阻碍了分子工具在理解基因组进化和育种新品种中的应用。我们通过基因分型通过测序对源自四倍体（4x = 36）“ A12359”的第一代自交种群进行基因分型。用3,544个标记构建了18个连锁组（LG）的高密度遗传图谱。比较基因组分析显示，每一个的九个部分同源LG对狗牙根对应的1到9对染色体之一Oropetium thomaeum。两次嵌套的古祖先染色体融合（ρ6-ρ9-ρ6，ρ2-ρ10-ρ2）可能导致染色体数目从12减少到10。古染色体ρ12（ρ1-ρ12-ρ1，ρ6-ρ12-ρ6）导致在10至9染色体减少的节段性传播狗牙根基因组中。遗传图谱将有助于正在进行的全基因组序列装配，并有助于开发新品种的标记辅助选择（MAS）。