Reproduced from Crop Science. Published by Crop Science Society of America. All copyrights reserved. Genetic Diversity of Cynodon transvaalensis Burtt-Davy and Its Relatedness to Hexaploid C. dactylon (L.) Pers. as Indicated by AFLP Markers Y. Q. Wu,* C. M. Taliaferro, G. H. Bai, and M. P. Anderson ABSTRACT heights, C. transvaalensis cultivars such as ‘Florida’ and ‘Uganda’ have been used on sporting surfaces such as Cynodon transvaalensis Burtt-Davy (African bermudagrass) is val- golf course putting greens, bowling greens, and tennis ued as turf and for use in interspecific hybridization with C. dactylon (L.) Pers. var. dactylon to produce turf cultivars. Little information courts (Juska and Hanson, 1964; Roux, 1969). Charac- is available regarding the magnitude of genetic variation within the teristics that limit the use of C. transvaalensis as turf taxon. Accordingly, this study was undertaken to evaluate the genetic include relatively high fertility and water requirements, diversity among 14 C. transvaalensis accessions and to examine the summer decline in turf quality when temperatures are phylogenetic relatedness of C. transvaalensis, two hexaploid (2n = high (38°C), and intolerance to sustained very low 6x = 54) C. dactylon var. dactylon accessions, two C. transvaalensis (3.2 mm) mowing heights (Juska and Hanson, 1964). by hexaploid C. dactylon var. dactylon interspecific tetraploid (2n = Information on the magnitude of variation within C. 4x = 36) F 1 hybrids, and one putative tetraploid C. dactylon var. dac- transvaalensis is limited. Cynodon transvaalensis plants tylon by C. transvaalensis triploid (2n = 3x = 27) F 1 hybrid. Fluores- cence-labeled amplified fragment length polymorphism (AFLP) DNA were described by de Wet and Harlan (1971) as being profiling was used to study the genetic relationships among these very uniform in appearance. However, substantial varia- accessions. A total of 381 polymorphic AFLP markers were amplified tion for morphological and adaptation traits has been from 13 primer combinations. The 14 C. transvaalensis accessions observed in segregating populations of C. transvaalensis and the putative triploid F 1 hybrid clustered into one group and had (Taliaferro, 1992). The most important use of C. trans- genetic dissimilarity coefficients ranging from 0.01 to 0.51. The 14 C. vaalensis has been in interspecific hybridization with transvaalensis accessions had genetic dissimilarity coefficients ranging tetraploid C. dactylon var. dactylon to produce clonally from 0.01 to 0.34. The C. dactylon var. dactylon accessions and the propagated F 1 hybrids. Many turf bermudagrass culti- two tetraploid F 1 hybrids clustered in the second group, with genetic vars, including the industry standards ‘Tifgreen’ and dissimilarity coefficients ranging from 0.17 to 0.33. The tetraploid F 1 hybrids were more closely related to C. dactylon var. dactylon than ‘Tifway’, were produced by this method (Burton, 1973, to C. transvaalensis, while the opposite was true for the putative 1991; Alderson and Sharp, 1995). However, relatively few triploid F 1 hybrid. The results indicate the presence of genetic diversity C. transvaalensis accessions have been used in breeding, in C. transvaalensis that could be exploited in intra- and interspecific genetic studies, or as commercial turf cultivars (Taliaferro, breeding improvement. 1992, 1995). Few hexaploid Cynodon plants have been reported, one being C. dactylon cv. ‘Tifton 10’ (Hanna et al., 1990). C ynodon transvaalensis (African bermudagrass) Tifton 10 originated as a vegetative introduction col- is valued as turf and for use in interspecific hybrid- lected by G.W. Burton in 1974 in Shanghai, China. Its ization with C. dactylon var. dactylon to produce turf major distinguishing features are coarse-textured fo- cultivars. African bermudagrass, a diploid (2n = 2x = liage with a natural dark bluish-green color, rapid estab- 18) species, is indigenous to the southwestern Transvaal lishment rate, and early green-up in spring (Hanna et and the northern part of the central Cape Province of al., 1990). The morphological characteristics of Tifton South Africa (Harlan et al., 1970a) where it is found 10 are most consistent with plants classified as C. dac- primarily near wet sites (Harlan et al., 1970b). Plants tylon var. dactylon in Harlan et al.’s (1970b) taxonomic of C. transvaalensis are distinctive because of their small classification for the genus Cynodon. We have crossed size, yellow-green color, erect narrow leaves, and two C. transvaalensis with Tifton 10 to produce tetraploid to four racemes per inflorescence with the spikelets F 1 plants. loosely arranged on the racemes (Harlan et al., 1970b). DNA profiling has been used to estimate genetic re- Cynodon transvaalensis is adapted to much cooler cli- latedness among Cynodon plants. DNA amplified finger- mates and is more winter hardy than needed in its natu- printing (DAF) was used to identify cultivars and study ral distribution (Harlan et al., 1970a). The rhizomatous and the origin of off-types found in cultivars (Caetano-Anol- stoloniferous plants spread to form a dense sod because of les, 1998; Caetano-Anolles et al., 1995; Ho et al., 1997; high shoot density. Because of their dense sod, fine leaf Anderson et al., 2001). Assefa et al. (1999) used DAF texture, and ability to tolerate relatively low mowing to assess genetic relatedness within and among eight Cynodon taxa. Roodt et al. (2002) used random ampli- Y.Q. Wu, C.M. Taliaferro, and M.P. Anderson, Plant and Soil Sciences Dep., Oklahoma State Univ., Stillwater, OK 74078; G.H. Bai, USDA- fied polymorphic DNA (RAPD) profiles to determine ARS/Dep. of Agronomy, Kansas State Univ., Manhattan, KS 66506. genetic relatedness of Cynodon cultivars in South Africa Received 19 April 2003. Turfgrass Science. *Corresponding author and to assess genetic variation. Zhang et al. (1999) and (yanqi@okstate.edu). Published in Crop Sci. 45:848–853 (2005). doi:10.2135/cropsci2003.913 Abbreviations: AFLP, amplified fragment length polymorphism; DAF, DNA amplification fingerprinting; RAPD, random amplified  Crop Science Society of America 677 S. Segoe Rd., Madison, WI 53711 USA polymorphic DNA; RFLP, restriction fragment length polymorphism. 848 Published online March 28, 2005