Some effects of hop latent viroid on two cultivars of hop (Humulus lupulus) in the UK

Abstract

SUMMARYSome effects of infection by hop latent viroid (HLVd) on two commercial plantings of hop, one each of two high alpha‐acid cultivars, are described. The cultivar Omega was severely affected: yield of cones and individual cone weights from infected plants were both lower than from uninfected plants by c. 35% and the alpha‐acids content (as assessed by HPLC) of the cones c. 30% lower. Wye Northdown was less severely affected: cone weight was 8% less (though this was not statistically significant) and alpha‐acids content lower by c. 15%. In both cultivars beta‐acids were higher in infected plants which, together with differences in other chemical components, suggested that cones on infected plants had matured, or were maturing, earlier than those on uninfected plants.These effects, together with the previous finding that HLVd occurs frequently in some cultivars (Barbara, Morton & Adams, 1990), suggest that HLVd is a potentially important constraint on hop production in the UK and should be eliminated if possible.