Molecular analysis of genetic variation among alfalfa (Medicago sativa L.)and Medicago ruthenica clones

Medicago ruthenica (L.) Ledebour is an allogamous diproid (2n = 2x = 16) pe rennial indigenous to Siberia, Mongolia and Manchuria with a remarkable abi lity to survive mechanical and physiological stress. The possibility of hyb ridizing alfalfa (Medicago sativa L.) and M. ruthenica is being investigate d. The objective of the current research was to conduct a molecular assessm ent of genetic relatedness and inter- and intra-specific genetic variation in cultivated alfalfa (2n = 4x = 32) and M. ruthenica. Seventeen alfalfa cl ones, selected randomly from the broad-based population W10- AC3, and 17 ag ronomically superior M. ruthenica clones, tracing to 17 collection sites in Inner Mongolia, were studied using Random Amplified Polymorphic DNA (RAPD) , Anchored Microsatellite Priming (AMSP), and Simple Sequence Repeat (SSR) analyses of genomic DNA. Mean genetic distances (GD) within M. ruthenica an d alfalfa clones were 0.5 and 0.56, respectively, based on RAPD/AMSP data, and 0.29 and 0.40, respectively, based on SSR data. Alfalfa and M. ruthenic a were genetically distant (RAPD/AMSP GD = 0.73); however, this difference does not necessarily preclude the possibility of interspecific hybridizatio n, although the use of techniques such as bridge crossing, embryo culture r escue and/or protoplast fusion may be necessary.