Efficiency of eradication of four viruses from garlic (Allium sativum) by meristem-tip culture

Mechanical inoculation tests and ELISA with sap from garlic plants used for sanitation by meristem-tip culture revealed four viruses, viz. garlic common latent virus (GCLV) (carlavirus), the garlic strains of leek yellow stripe virus (LYSV-G), onion yellow dwarf virus (OYDV-G) (aphid-borne potyviruses), and onion mite-borne latent virus (OMbLV-G) (taxonomically unassigned virus). The same tests performed on explants grownin vitro showed elimination efficiencies of 100% for LYSV-G, 92% for OYDV-G, 62% for GCLV, and less then 54% for OMbLV-G.Meristem tips excised from garlic cloves and bulbils, 0.15–1.0 mm in size, were tested for regeneration and efficiency of virus elimination after transfer to Murashige and Skoog medium. Successful regeneration into plantlets was obtained with 71% of the meristems from cloves and 72% of those from bulbils, but virus elimination was easiest from cloves: 38% of all explants from cloves and 25% of those from bulbils were virus-free. The efficiency of elimination increased with increasing weight of the cloves, irrespective of the virus. Small tip size seemed to favour virus elimination, but sizes smaller than 0.4 mm led to increasing failure of regeneration.Micropropagation was most successful when cytokinins were omitted from the medium and the garlic shoot was split. Multiplication factors of 3–6 were obtained.