Mature plant resistance for stripe rust and scald cannot be reliably and efficiently screened in the glasshouse or in the seedling growth stages. Most screening for these diseases was conducted in inoculated field nurseries. Emphasis was placed on stripe rust and septoria in wheat and scald in barley. The project successfully obtained disease resistance data for varieties and breeding lines in the wheat and barley breeding programs in South Australia and, to a lesser extent, lines from other breeding programs in the southern region. The project also provided advice on the most appropriate breeding strategies for the control of the priority diseases, particularly scald, leaf rust and mildew in barley and stripe rust and septoria in wheat.
This has enabled priorities to be set for the breeding programs and chemical companies in planning future strategies. This project has identified, publicised and explained the incidence and severity of the leaf and stem diseases in wheat and barley to growers, industry and research scientists. To provide a resource base for information and advice on leaf and stem diseases of cereals to growers, industry, advisers and scientists.To determine the incidence, importance and seek control methods for leaf and stem diseases of cereals in the southern region.To collaborate in the production of disease resistant varieties with the wheat and barley breeding programs in the southern region.This project was a continuation of a similar one funded by the Grains Industry Research Committee of South Australia. Continuous sowing of wheat (particularly in 1996) has also led to an increase in yellow leaf spot (tan spot). Minimum tillage and stubble retention have also led to Arno Bay blotch becoming a problem disease on the Eyre Peninsula and in the Victorian Mallee and to a lesser degree in other areas in recent years. Earlier sowing, made possible by the advent of improved herbicides, has increased the presence of leaf scald. For this reason, it is important in breeding for resistance that a diversity of resistance genes is deployed and that reliance is not placed in too few genes.Ĭhanges in farm management practices have influenced the incidence of crop diseases. For several pathogens, notably barley scald and the rust diseases, there is a risk that varieties will lose their resistance to new races of the pathogens. This involves the identification of sources of resistance, identifying variation in disease-causing pathogens and the screening of large numbers of breeders’ lines either in field nurseries or under more controlled environment conditions. It has long been recognised that the most effective, economic and sustainable means of controlling crop diseases is the use of resistant varieties. In addition, further economic losses were incurred as many deliveries were downgraded from malting as a result of higher screenings.
In most cases, leaf scald was the cause of yield loss in the untreated plots. The barley variety evaluation trials conducted throughout South Australia in 1992 showed an average yield gain across all sites of 22% when Schooner plots were sprayed with fungicide. In 1992, early sowing and a wet spring resulted in stripe rust, leaf rust and septoria tritici blotch in wheat and scald, leaf rust and Arno Bay blotch (spot form net blotch) in barley, causing severe losses over wide areas. Depending on seasonal conditions, losses can be slight, as in 1993, or very significant as in 1992.
Leaf and stem diseases of wheat and barley are responsible for large losses in yield in these crops. Business development and commercialisation