The Population Genetic Structure of Diploid Medicago sativa L. Germplasm
- Cite this paper as:
- Sakiroglu M., Doyle J.J., Brummer E.C. (2010) The Population Genetic Structure of Diploid Medicago sativa L. Germplasm. In: Huyghe C. (eds) Sustainable use of Genetic Diversity in Forage and Turf Breeding. Springer, Dordrecht
The three subspecies Medicago sativa subsp. caerulea (syn. coerulea), M. sativa subsp. falcata, and M. sativa subsp. hemicycla are considered to form the diploid gene pool of cultivated alfalfa (M. sativa subsp. sativa). The diploid gene pool is underutilized in breeding programs despite extensive morphological variation and the simplicity of disomic inheritance. Population structure and the genetic basis of the current morphologically-based classification of diploid germplasm are not known. We analyzed the population genetic structure of wild diploid alfalfa germplasm by evaluating 374 individual genotypes from 120 accessions, representing the broad natural variation of the three subspecies, with 89 microsatellite markers. We found that the three subspecies formed distinct clusters, with evidence of further subdivision of falcata and caerulea into two subclusters each. The genetic distinction between the two falcata subclusters is more definitive than that of the two caerulea groups. Genome composition suggests extensive gene flow where subspecies and/or groups within subspecies grow sympatrically. The results will help breeders identify appropriate diploid accessions to maximize diversity in applied germplasm development.