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ARS Home » Pacific West Area » Pullman, Washington » Plant Germplasm Introduction and Testing Research » Research » Publications at this Location » Publication #221177
Title: Conserving alfalfa wild relatives: is past introgression with Russian varieties evident today?

Author
item Greene, Stephanie
item Kisha, Theodore
item DZYUBENKO, NIKOLAI - N.I. VAVILOV INSTITUTE

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2007
Publication Date: 10/1/2008
Citation: Greene, S.L., Kisha, T.J., Dzyubenko, N.L. 2008. Conserving alfalfa wild relatives: is past introgression with Russian varieties evident today?. Crop Science 46:1853-1864.

Interpretive Summary: Central Asia supports a rich concentration of wild alfalfa (Medicago sativa L.) relatives that freely cross with domesticated alfalfa. These are important genetic resources that need to be conserved. Using SSR and AFLP markers we evaluated six wild populations of M. sativa nothossp. varia collected in Northwestern Kazakhstan, to determine if there was any evidence that gene flow had occurred between wild and domesticated alfalfa, grown historically in the past. There was no difference in population genetic parameters between the cultivated and wild accessions, however diversity was less in the wild then in the cultivated populations. Cluster analysis and principle component analysis showed clear separation between wild and cultivated. We found limited evidence of admixture among the wild and cultivated forms and concluded that three of the six wild populations stood out as candidates for in situ conservation based on their uniqueness and lack of contamination with cultivated alfalfa.

Technical Abstract: Central Asia, particularly Kazakhstan, supports a rich concentration of wild alfalfa (Medicago sativa L.) relatives. Because they freely cross with domesticated alfalfa, they are important genetic resources. When identifying in situ populations to conserve, contamination of wild populations with domesticated alleles is an important consideration. We evaluated population structure and introgression between six wild populations of M. sativa nothossp. varia collected in Northwestern Kazakhstan, and five traditional Russian cultivars historically grown in the same region using two AFLP primer pairs and six SSR loci. There was no difference between the cultivated and wild accessions for number of alleles or percent polymorphic loci, however, gene diversity was less in the wild then in the cultivated populations. Cluster analysis and principle component analysis showed clear separation between wild and cultivated. Genetic differentiation among the cultivars was less then among the wild populations. Using a Bayesian approach, we found limited evidence of admixture among the wild and cultivated forms, although more admixture was evident in wild populations collected in less remote areas. Based on marker data we concluded that three of the six wild populations stood out as candidates for in situ conservation based on their uniqueness and lack of admixture with cultivated forms.