Submitted to: National Allium Research Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/2/2006
Publication Date: 12/7/2006
Citation: Pappu, H., Hellier, B.C., Dugan, F.M. 2006. Screening the National Plant Germplasm System's Garlic Collection for Viruses. Proceedings 2006 National Allium Research Conference, December 7-8, 2006, College Stationk TX, p 35-36.
Technical Abstract: The USDA-ARS Western Regional Plant Introduction Station (WRPIS) collects, maintains, and distributes garlic (Allium sativum) accessions as part of the National Plant Germplasm System. In the regeneration process, accessions are grown under field conditions at the WRPIS farm in Pullman, Washington. In June 2004, several WRPIS accessions developed severe symptoms indicative of viral infection. Using ELISA, and PCR followed by cloning and sequence analysis, we found that Garlic common latent virus (GCLV), Leek yellow stripe virus (LYSV), and Onion yellow dwarf virus (OYDV) were present. This led to a more extensive evaluation of the collection in 2005 and 2006. Over 200 accessions were rated for the incidence of symptomatic plants in July 2005 and June 2006. Symptoms indicative of virus infection were noticed in a majority of the accessions while some remained disease free. Incidence of symptomatic plants ranged from less than 10% to 100% in individual accessions. Tissue from symptomatic plants from several accessions was collected for laboratory testing. ELISA was used to determine the identity of the viruses involved. Each sample was tested separately for the following viruses that are known to infect garlic and onions: GCLV, LYSV, OYDV, Shallot latent virus (SLV), Tobacco rattle virus (TRV) and Iris yellow spot virus (IYSV). Results indicated that the plants tested were infected with GCLV, LYSV or OYDV with some plants showing mixed infections. None of the plants tested were positive for IYSV, SLV nor TRV. While the majority of accessions with symptomatic plants were found positive for the above viruses, some accessions remained uninfected indicating a differential response to viral infection and the existence of potential genetic resistance in garlic germplasm.