Narcissus (Narcissus spp.) bulbs were used to investigate contagious viral retention in the dormant stage. The amplified polymerase chain reaction (PCR) bands were screened using universal potyvirus primers and sequenced to identify specific viruses. To identify individual viruses, primers for specific viruses were designed, and reverse transcription (RT)-PCR was performed. The PCR fragments were sequenced and compared by phylogenetic analysis. Three potyviruses, cyrtanthus elatus virus A (CyEVA), narcissus yellow stripe virus (NYSV), and narcissus late season yellows virus (NLSYV) were singly or doubly detected in 18 samples from six cultivars of the 38 samples representing eight cultivars that were tested. Based on RT-PCR using specific primers, CyEVA was detected in the split corona daffodil cv. Orangery. NLSYV and NYSV frequently occurred as co-infections with each other in the double daffodil cv. Tahiti, and the N. cyclamineus daffodil cv. Tete-a-tete and cv. Tete Boucle. Results has shown that at least three potyviruses are present in imported Narcissus bulbs.

Introduction
Materials and Methods
    Bulb sources of Narcissus
    Extraction of total RNAs from the bulb tissues
    Reverse transcription (RT)
    Polymerase chain reaction (PCR) using universalprimers for potyvirus
    Sequencing of PCR products amplified usingpoty-universal primers
    Design of primers for specific virus detectionand PCR
    Sequences generated from Narcissus isolates ofCyEVA, NYSLV, and NYSV, and phylogenetic construction
Results
    Screening and identification of potyviruses inbulb tissues
    Application of virus-specific primers for diagnosis
    Identification of virus isolates obtained fromNarcissus spp. based on phylogeny
Discussion
Acknowledgment

• Eun Song Heo(Department of Horticultural Biotechnology and Landscape Architecture, Seoul Women’s University, Seoul 01797, Korea)
• Sun Hee Choi(Department of Horticultural Biotechnology and Landscape Architecture, Seoul Women’s University, Seoul 01797, Korea) Corresponding author