Abstract: [objective] The study conducted to obtain the full-length cDNA of BSMV-CH RNA1, analysis its molecular character and determine its genetic relationship to foreign strains.[method] The full-length cDNA of BSMV-CH RNA1 was obtained by RT-PCR from the total RNA extracted from the barley leaves infected by BSMV-CH, and cloned into pMD18 vector for sequencing. The sequence together with sequences of BSMV RNA1 available in Genbank was used for nucleotide identity analysis and molecular phylogenetic reconstruction. [result] The full-length cDNA of BSMV-CH RNA1 was 3795bp（AY789693） with a 5`cap in the 5`-terminal, a polyA structure and a tRNA-like structure in the 3`terminal. An open reading frame(ORF) was found in BSMV-CH RNA1. The ORF was 3417bp and deduced to encode the replicase with 1138 amino acids. BSMV-CH RNA1 shares 95.4~95.6% nucleotides identity with that of other strains, and the replicase shares 94.9~95.2% and 96.5~96.8% identities with that of other strains in nucleotides and amino acids, respectively. BSMV-CH RNA1 has more polyA in the 3`terminal than that of other stains. [conclusion] The genetic relationship between BSMV-CH or CV42 and other strains is obviously lower than that among other strains. BSMV-CH and CV42 are relatively close to each other. But BSMV-CH is a new strain that is different from CV42.

Key words: Barley stripe mosaic virus, molecular character, identity, genetic relationship