Susceptibility of Australian wheats to Pyrenophora tritici-repentis

Abstract

The response of Australian wheats to yellow spot caused by Pyrenophora tritici-repentis has been examined under controlled conditions with a juvenile-plant screening system. About three-quarters of contemporary Australian wheats are highly susceptible to the disease and very few cultivars possess useful levels of resistance. Also, the majority of Australian wheats now undergoing final evaluation before releasing are highly susceptible to yellow spot. Modern wheats grown in Queensland and northern New South Wales are, as a group, more susceptible than those they replaced, and this may have contributed to the upsurge in yellow spot in the region. In two comparisons between ratings on juvenile plants under controlled conditions with field disease assessments and yield measures, the juvenile plant ratings and field disease assessments explained similar proportions of the variation in yield measures.