Abstract:

In this study，tall fescue EST-SSR markers were developed using two ways of transferring from other crops and designing from EST sequences of tall fescue. Genetic diversity of tall fescue was analysed by these markers. Transferability of 732 EST-SSRs primer pairs from wheat，barley，maize， sorghum and rice was analysed in tall fescue. Of which，406（55.46%）primer pairs showed effective amplification. Besides，in the 63 853 tall fescue EST sequences from GenBank/dbEST，420 EST sequences（0.658%）containing SSRs were found. Among these SSRs of tall fescue，trinucleotide motifs appeared to be the most abundant SSRs（43.33%），followed by dinucleotide（33.57%）. For the motifs of dinucleotide and trinucleotide，CT/GA（16.90%）and CAG/GTC（10.63%）were the most abundant motif respectively. One hundred and eight primer pairs were designed by Primer 5.0 software and synthesized by Shanghai Sunny Company. PCR analysis showed that，92 primer pairs had stable and distinctive bands in tall fescue. From EST-SSRs of 5 crops（406）and tall fescue（92），81 EST-SSR primers were selected randomly to detect the polymorphism in the 12 tall fescue cultivars（strain），and 79 primer pairs（97.53%）showed polymorphism with totally 133 alleles，1.68 alleles per primer in average. The PIC（Polymorphism information contents）for each polymorphic primer varied from 0.14 to 0.66，with an average of 0.48. Clustering analysis indicated that the 12 tall fescue cultivars were clustered into 5 groups based on 0.61 of GS. GroupⅠincludes Explosiveness and Fawn，group Ⅱ includes Powerful，Plantation and Triple A，group Ⅲ includes Kochis 3 and Lexus，group Ⅳ includes Athena 2，Jaguar 3，Exerion and TF160，group Ⅴ includes Fireway.

Key words: tall fescue, EST-SSR, transferability, marker development, genetic diversity