Molecular breeding of wheat lines for multiple rust and Fusarium head blight resistance

Abstract

Bread wheat is a widely cultivated crop with production that is often negatively influenced by disease outbreaks. Biological constraints in production include the wheat rusts (leaf rust, stem rust and stripe rust) and Fusarium head blight (FHB). Different strategies are available in the control of these important fungal diseases. However, resistance breeding remains the preferred option of control as it lowers the risk of disease outbreaks and is a more cost effective and environmentally friendly approach. Many effective rust and FHB resistance genes have been discovered and successfully deployed through resistance breeding worldwide. However, some of these genes, when deployed singly, are vulnerable to evolving pathogens. In this study we aimed to develop wheat lines with the prospect of durable resistance against the rusts and FHB through combining eight resistance genes/quantitative trait loci; Lr19, Lr34/Yr18/Sr57/Pm38/Ltn1, Sr2/Yr30, Sr26, Sr39, Fhb1, Qfhs.ifa-5A-1 and Qfhs.ifa-5A-2 into a single wheat plant using marker-assisted selection. Cross and self-pollinated populations were developed to increase the frequency and homozygosity levels of resistance genes in progeny. Molecular markers were furthermore applied to determine the identity of the high molecular weight-glutenin subunits (HMW-GS) and to screen for the presence of the 1BL.1RS translocation in the final populations. We were successful in developing wheat plants containing complex sources of rust and FHB resistance and confirmed the presence of HMW-GS markers linked to strong dough strength and good bread making qualities in these genotypes.