Fusarium head blight resistance pre-breeding

 

​Fusarium head blight (FHB), also known as Scab, is one of the most destructive diseases of wheat in the world.

Fusarium graminearum (Gibberella zeae) is the predominant causal organism on wheat as well as barley and has become an increasing concern for farmers/researchers within the expanding irrigation production areas of South Africa.

Annually wheat lines with new resistance to FHB are imported into the country from different corners of the world. This is often done through direct germplasm requests from established collaborators based in Europe, China, Japan and the United States of America (USA).  Additional, novel resistant material is also obtained from the annual FHB nurseries compiled by the Maize and Wheat Improvement Centre (CIMMYT) and the United States Department of Agriculture.  Often these resistant sources have been well characterised and documented as FHB resistant to strains of FHB found elsewhere.

The imported resistance sources are extensively screened in both the field and glasshouse each year to quantify or validate resistance levels to local FHB strains.  Only the confirmed resistant sources are then included in a specific pre-breeding backcross programme. This research team makes use of a combination of phenotypic selection as well as marker-assisted selection for specific FHB resistance genes/QTL.

The current focus of this pre-breeding programme is to increase the diversity of FHB resistance donors available to breeder as well as increase the overall FHB resistance level present in future irrigated spring wheat cultivars to avoid dependence on the Sumai 3 derived resistance which has, to date been most used.