Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2004
Publication Date: 3/28/2005
Citation: Wu, Y.Q., Taliaferro, C.M., Bai, G., Anderson, M.P. 2005. Genetic diversity of cynodon transvaalensis burtt-davy and its relatedness to hexaploid c. dactylon (l.) pers. as indicated by aflp markers. Crop Science. 45:848-853. Interpretive Summary: Cynodon transvaalensis is a grass species which has been used as turf and hybridized with C. dactylon var. dactylon (another grass species) to produce high quality turf bermudagrass cultivars. Little information exists on the magnitude of genetic variation within the indigenous species from South Africa. In this report, we demonstrated the presence of substantial variation among C. transvaalensis accessions using new DNA marker technology and characterized their relatedness to C. dactylon var. dactylon and their interspecific hybrid derivatives. The results suggest that sufficient genetic variation within C. transvaalensis is available for genetic improvement of turf cultivars.
Technical Abstract: C. transvaalensis Burtt-Davy (African bermudagrass) is valued as turf and used in interspecific hybridization with C. dactylon (L.) Pers. var. dactylon to produce hybrid turf cultivars. The diploid (2n=2x=18) species of C. transvaalensis is indigenous to South Africa and only a few accessions have been available for breeding or genetic study with little information available regarding 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 interspecific tetraploid (2n=4x=36) F1 hybrids from crosses between C. transvaalensis and hexaploid C. dactylon var. dactylon, and one putative triploid (2n-3x=27) F1 hybrid from the cross between C. dactylon var. dactylon and C. transvaalensis. 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 fragments were amplified from 13 primer combinations. The 19 accessions clustered into two major groups. The 14 C. transvaalensis accessions and the putative triploid F1 hybrid clustered into one group with 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 F1 hybrids clustered in the second group, with genetic dissimilarity coefficients ranging from 0.17 to 0.33. The tetraploid F1 hybrids were closer 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 substantial genetic diversity in C. transvaalensis that could be exploited in intra- and inter-specific breeding application.