RT-PCR Detection and Molecular Variability of Apple stem pitting virus Genetic variation analysis of the coat protein of Grapevine rupestris stem pitting associated virus isolates from China Detection and sequence analysis of Hop stunt viroid in grapevine rootstock from France First report of Cucumber green mottle mosaic virus(CGMMV)in Hunan Province RT-PCR detection and sequence analysis on three grapevine viruses from Xinjiang Uyghur Autonomous Region