Inferring population structure and genetic diversity of broad range of wild diploid alfalfa (Medicago sativa L.) accessions using SSR markers

• Published in: Theoretical and applied genetics 2010-08, Vol.121 (3), p.403-415
• Main Authors: Şakiroğlu, Muhammet, Doyle, Jeffrey J, Charles Brummer, E
• Format: Article
• Language: English
• Subjects: Agriculture; Analysis; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Chromosome Mapping; Chromosomes, Plant - genetics; Classical genetics, quantitative genetics, hybrids; Cultivars; Diploidy; DNA, Plant - genetics; Fundamental and applied biological sciences. Psychology; Genetic diversity; Genetic Markers - genetics; Genetic Variation; Genetics of eukaryotes. Biological and molecular evolution; Genomics; Genotype; Germplasm; Life Sciences; Medicago sativa; Medicago sativa - genetics; Morphology; Original Paper; Plant Biochemistry; Plant Breeding/Biotechnology; Plant Genetics and Genomics; Polymerase Chain Reaction; Pteridophyta, spermatophyta; Repetitive Sequences, Nucleic Acid; Soil sciences; Taxonomy; Vegetals
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-010-1319-4

Diversity analyses in alfalfa have mainly evaluated genetic relationships of cultivated germplasm, with little known about variation in diploid germplasm in the M. sativa-falcata complex. A collection of 374 individual genotypes derived from 120 unimproved diploid accessions from the National Plant Germplasm System, including M. sativa subsp. caerulea, falcata, and hemicycla, were evaluated with 89 polymorphic SSR loci in order to estimate genetic diversity, infer the genetic bases of current morphology-based taxonomy, and determine population structure. Diploid alfalfa is highly variable. A model-based clustering analysis of the genomic data identified two clearly discrete subpopulations, corresponding to the morphologically defined subspecies falcata and caerulea, with evidence of the hybrid nature of the subspecies hemicycla based on genome composition. Two distinct subpopulations exist within each subsp. caerulea and subsp. falcata. The distinction of caerulea was based on geographical distribution. The two falcata groups were separated based on ecogeography. The results show that taxonomic relationships based on morphology are reflected in the genetic marker data with some exceptions, and that clear distinctions among subspecies are evident at the diploid level. This research provides a baseline from which to systematically evaluate variability in tetraploid alfalfa and serves as a starting point for exploring diploid alfalfa for genetic and breeding experiments.