Abstract: Astragalus sinicus L. is a traditional green manure used in rice field in China. To identify Astragalus sinicus L varieties in agricultural production, we developed SSR molecular markers by using biotinylated (AG)_15,(CT)₁₅, (AC)₁₅, (GT)₁₅ probes and streptavidin coated magnetic beads, the SSR sequences were enriched from A. sinicus genome. Of the 950 transformantsselected from the library constructed by obtained fragments, 127 clones were confirmed as SSR insert by PCR identification and final sequencing, with a SSR enrichment efficiency of 15.8%. By deleting the duplicated and unavailable sequences, 33 SSR loci were used for primer design. After nine A. sinicus varieties were sampled for analysis of the genetic diversity based on these SSR primers, only six SSR primer pairs amplified a total of 18 stable and repeatable polymorphic bands within tested plant samples. At the level of variety population of A. sinicus, based on these SSR loci we calculated the percentage of polymorphic band ranging from 50% to 100%, effective number of alleles ranging from 1.19 to 1.64, Nei’s gene diversity ranging from 0.13 to 0.38, and Shannon’s information index ranging from 0.22 to 0.56; the selected six primer pairs could completely distinguish the tested plant samples, and the application of these SSR loci for fingerprinting identification of variety was proved to be feasible to A. sinicus. Based on similar coefficient generated from six SSR loci, we clustered nine tested varieties of A. sinicus mainly into two groups, which had no certain linkage to the traditional classification of variety according to its growth period. The studyopened up a prospect of using SSR molecular marker for genetic analysis, variety identification, and protection of intelligent property in commercial breeding of A. sinicus.

Key words: Astragalus sinicus L., Simple sequence repeat (SSR), Genetic diversity, Streptavidin coated magnetic bead, Variety identification