Abstract: Newcastle disease virus strain GD1002, isolated from the diseased ducks in Guangdong province in 2010, was velogenic according to the pathogenetic tests and highly pathogenicity to duck. The results of virulence determination showed that the MDT, ICPI and IVPI were 56.0 h, 1.64 and 2.29, respectively, belonged to velogenic strain virulence criterion. The F gene of GD1002 strain was amplified by reverse transcription polymerase chain reaction (RT-PCR). The cleavage motif ¹¹²R-R-Q-R-R-F¹¹⁷ of F protein was identical to the characteristic of velogenic strain. For genotyping, phylogenetic tree based on the nucleotide 47 to 420 nt of the F gene were performed using the isolate and other NDV sequences obtained from GenBank. The results revealed that the isolate belonged to genotype Ⅸ. And the results of nucleotide sequence homology and evolutionary processes analyses showed that the isolate had a close relationship with F₄₈E₉, JS/1/97/Ch and FJ/1/85/Ch strains.

Key words: duck; Newcastle disease virus; F gene; cloning; sequence analysis