Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/31/2003
Publication Date: 7/31/2003
Citation: He, C.N., Xia, Z., Campbell, T.A., Bauchan, G.R. 2003. Development and characterization of simple sequence repeat (SSR) markers in medicago sativa [abstract]. Agronomy Abstracts. P1027.
Technical Abstract: Microsatellite or simple sequence repeat (SSR) markers are codominant and hypervariable molecular markers that are being widely used in genetic mapping, phylogenetic studies and marker-assisted selection. Currently, there are very few SSR markers available for use in alfalfa. Thus, this study was conducted to develop microsatellites from alfalfa genomic libraries in order that they could be used in genetic studies. Genomic DNA was isolated from the alfalfa germplasm W10 and libraries were constructed with the vector pUC19 following restriction digest. Probes containing simple sequence repeats of CT, CAT, GAT were used for screening the colonies carrying inserts from the genomic libraries. A total of 118 colonies with a positive signal were identified and sequenced. Of the 118 sequences, 14 sequences did not contain any SSR, 12 were redundant and thus eliminated. Among the remaining 92 sequences, 38 could not be used for PCR primer design due to the terminal presence of SSRs or unusable DNA sequences, thus 54 DNA sequences were used for primer design. After PCR testing, the vast majority (51) of the 54 PCR primer pairs amplified the expected PCR fragments while the other three did not produce any PCR products. These primers were used to screen 10 historically recognized alfalfa germplasm sources and germplasm collected in the wild in order to detect the genetic variation among them. A total of 36 (70.6%) out of 51 primer pairs generated polymorphisms among the germplasm. These 36 polymorphic primers for the SSR loci with CT, CAT and GAT repeats were used for genetic analysis and constructing a dendrogram for 16 Medicago germplasms.