Field resistance of oat cultivars to cereal root eelworm (Heterodera avenae)

Abstract

Oat cultivars were classified as resistant or susceptible to cereal root eelworm (Heteroaera avenae Woll.) by their reaction to the pathogen on the basis of visual symptoms and grain yields. The cultivars Alpha, Avon, Ballidu, Early Kherson, Fulghum, Fulmark, Kent, and Orient were more susceptible than New Zealand Cape. The relative efficiency of the oat cultivars in supporting the eelworm population was assessed following a period under volunteer pasture and fallow by measuring the depression in yield of a susceptible crop of Gabo wheat. Cultivars causing least depression were classified as inefficient hosts. Avon, Ballidu, and Kent, together with the resistant New Zealand Cape, were equally the least efficient hosts. Fulghum and Orient were between the least and most efficient host groups. Susceptibility was not necessarily associated with host efficiency, hence it is likely that different mechanisms govern susceptibility and host efficiency. Recognition of this is important in programmes aimed at the control of eelworm using cereals in rotation, or the breeding of resistant cultivars.