Reactions of Cereals To Populations of Heterodera Avenae in South Australia

Two wheat cultivars (AUS 10894 and AUS 90248) and one barley (cv. Morocco), were resistant to 20 populations of Heterodera avenae Woll. from southern Australia. No variations occurred in the reactions of 22 cultivars from an 'International Test Range', to 4 diverse poplations of H. avenae in South Australia. Except for one wheat (cv. Psathias), which was more susceptible than the resistant wheat (cv. AUS 10894), the reactions were similar to those reported with Victorian populations. Therefore, only one biotype seems likely for South Australia and it is probably the same as the Victorian biotype. Second-stage larvae which developed in the field at different locations had a constant width but varied in length. This variation in length did not occur when larvae were grown in a controlled environment.