ARS | Publication request: GENETIC DIVERSITY AMONG FORAGE BERMUDAGRASS (CYNODON SPP.): EVIDENCE FROM CHLOROPLAST AND NUCLEAR DNA FINGERPRINTING

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 12, 2002
Publication Date: October 1, 2002
Citation: KARACA, M., SAHA, S., ZIPF, A.E., JENKINS, J.N., LANG, D.L. GENETIC DIVERSITY AMONG FORAGE BERMUDAGRASS (CYNODON SPP.): EVIDENCE FROM CHLOROPLAST AND NUCLEAR DNA FINGERPRINTING. CROP SCIENCE. 2002. V.42.P.2118-2127.

Interpretive Summary: Bermudagrass breeders frequently encounter three major challenges: 1) for many of the 'ecotypes' selected from farmer fields there is a lack of knowledge of pedigree history and source of origin; 2) in general there is limited knowledge about the genome of the forage type bermudagrass, and 3) lack of suitable methods for genetic analysis. The high value of bermudagrass as a forage crop justifies new and innovative approaches toward its genomics. The objectives of this study were to characterize genetic relationship within 31 forage bermudagrass ecotypes and varieties using DNA fingerprinting. Genetic relationships within the 31 forage bermudagrasses were determined using a total of 472 polymorphic DNA markers generated by 15 Amplified Fragment Length Polymorphism (AFLP), 10 Chloroplast-specific Simple Sequence Repeat Length Polymorphism (CpSSRLP), 10 Random Amplified Polymorphic DNA (RAPD), and 10 Directed Amplification of Minisatellite-region DNA (DAMD) primers or primer pairs. Results indicated that forage bermudagrass lines have a narrow genetic base, ranging in genetic similarity (GS) from 0.60 to 0.97. The most genetically similar forage bermudagrass lines were 'Tifton 78 WH' and 'Tifton 78' (GS: 0.97), and 'McDonald' and Tifton 78 were the most genetically diverse bermudagrass lines (GS: 0.60). Ecotypes, 'Sumrall 007', 'Tanberg', 'Maddox', and 'Stallings' were related to known varieties. Results indicated that these DNA fingerprinting techniques will be useful to characterize genetic diversity within bermudagrass lines.

Technical Abstract: DNA-based fingerprinting has proven useful in several plant species including turf-type bermudagrass. Genetic analysis of forage bermudagrass lags behind other species. This research was undertaken to characterize genetic relationships among forage bermudagrass ecotypes and varieties. Genetic relationships within the 31 forage bermudagrass types were based on 472 polymorphic DNA markers generated from 15 Amplified Fragment Length Polymorphism (AFLP), 10 Chloroplast-specific Simple Sequence Repeat Length Polymorphism (CpSSRLP), 10 Random Amplified Polymorphic DNA (RAPD), and 10 Directed Amplification of Minisatellite-region DNA (DAMD) primers or primer pairs. Results showed that forage bermudagrass lines have a narrow genetic base, (genetic similarity 0.60 to 0.97). The most similar were 'Tifton 78 WH' and 'Tifton 78' (GS: 0.97), and 'McDonald' and Tifton 78 were the most genetically diverse lines (GS: 0.60). Ecotypes, 'Sumrall 007', 'Tanberg', 'Maddox', and 'Stallings' were only distantly related to known varieties. Thus these ecotypes were unique providing justification to classify as varieties. Close genetic relationships between some ecotypes and varieties were detected: McDonald to W. Feeder, 'Prairie 1', 'Prairie II', and 'Prairie III' to 'Grazer', 'Lott 1', 'Lott II', and 'Lancaster' to 'Callie', and Tifton 78 WH to Tifton 78. Although DNA markers could differentiate these ecotypes, additional molecular, cytological, and phenological evidences are required to confirm whether they should be new varieties.