Genetic Diversity of Cynodon transvaalensis Burtt‐Davy and Its Relatedness to Hexaploid C. dactylon (L.) Pers. as Indicated by AFLP Markers

Abstract

Cynodon transvaalensis Burtt‐Davy (African bermudagrass) is valued as turf and for use in interspecific hybridization with C. dactylon (L.) Pers. var. dactylon to produce turf cultivars. Little information is available regarding the magnitude of genetic variation within the taxon. Accordingly, this study was undertaken to evaluate the genetic diversity among 14 C. transvaalensis accessions and to examine the phylogenetic relatedness of C. transvaalensis, two hexaploid (2n = 6x = 54) C. dactylon var. dactylon accessions, two C. transvaalensis by hexaploid C. dactylon var. dactylon interspecific tetraploid (2n = 4x = 36) F1 hybrids, and one putative tetraploid C. dactylon var. dactylon by C. transvaalensis triploid (2n = 3x = 27) F1 hybrid. Fluorescence‐labeled amplified fragment length polymorphism (AFLP) DNA profiling was used to study the genetic relationships among these accessions. A total of 381 polymorphic AFLP markers were amplified from 13 primer combinations. The 14 C. transvaalensis accessions and the putative triploid F1 hybrid clustered into one group and had genetic dissimilarity coefficients ranging from 0.01 to 0.51. The 14 C. transvaalensis accessions had genetic dissimilarity coefficients ranging from 0.01 to 0.34. The C. dactylon var. dactylon accessions and the two tetraploid F1 hybrids clustered in the second group, with genetic dissimilarity coefficients ranging from 0.17 to 0.33. The tetraploid F1 hybrids were more closely related to C. dactylon var. dactylon than to C. transvaalensis, while the opposite was true for the putative triploid F1 hybrid. The results indicate the presence of genetic diversity in C. transvaalensis that could be exploited in intra‐ and interspecific breeding improvement.