Field experiments with spring barley resistant to cereal cyst nematode, 1965-1968

Two bulk populations of spring barley lines differing in respect of a single dominant gene for cereal cyst nematode (Heterodera avenue) resistance were used in trials over 4 years to assess the effect of the nematode on grain yield. On an infested site the resistant lines consistently and significantly out-yielded the susceptible lines by an average of 9 % over the 4 years. On non-infested sites, there was no difference in yield between the resistant and susceptible lines. To measure changes in the cereal cyst nematode population under continuous barley cultivation, the resistant and susceptible lines were each sown at the infested site on the same plots for 4 consecutive years. The cereal cyst nematode population declined under both susceptible and resistant barley, but more rapidly under the latter. Migratory nematodes, mostly Pratylenchus minyus, were latterly prevalent on all plots. There was no detectable change in the pathogenicity of the cereal cyst nematode population after 3 years of growing resistant barley.