1 Jilin Academy of Agricultural Sciences，Gongzhuling 136100，Jilin，China；2 School of Life Science，Changchun Normal University，Changchun 130032，Jilin，China；3 Wuhu Institute of Technology，Wuhu 241000，Anhui，China
Abstract：Onion yellow dwarf virus（OYDV）is one of the major viruses harming Allium plants． A method of real-time fluorescence RT-PCR was established and optimized by using a pair of specific primers according to conserved sequence from the coat protein gene of OYDV．Then its specificity，sensitivity and repeatability were verified．Results displayed that the standard curve Ct value and logarithmic of template copy number showed a good linear relationship．The correlation coefficient was 0.996 and amplification efficiency was 95.921%．There was no crossing reaction with Shallot virus X（SVX） and Shallot latent virus （SLV）．The lowest detection limit was 2.0 × 102 copies · μL-1，about 1 000 times higher than that of the routine RT-PCR．Both variable coefficients of intra-assay and inter-assay were less than 2%，having good repeatability．This experiment utilized this method and detected 45 samples collected respectively from suspected infectious tillering onion（shallot）and garlic．The detection rates were 40.00 and 6.67 percentage point higher than those by conventional RT-PCR assay，respectively，reflecting more objectively the toxic status of samples．The OYDV real-time fluorescence RT-PCR method established by this experiment has good specificity，sensitivity and repeatability．It can be used for detecting OYDV samples in the fields and provide technical support for effective prevention and control of OYDV．
