Abstract
The release of commercial wheat cultivars resistant to stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), remains one of the primary objectives in many breeding programs. Previous studies of adult plant resistance derived from the winter wheat cultivar Cappelle-Desprez identified the quantitative trait loci (QTL) QYr.ufs-2A, QYr.ufs-2D, QYr.ufs-5B and QYr.ufs-6D to affect stripe rust under South African conditions. Phenotypic field assessment, fluorescence microscopy and molecular analysis were used to characterise recombinant inbred lines differing in number and combinations of these QTL. Besides the confirmation of enhanced resistance through co-occurring resistance loci, varying levels of defence, conditioned by different QTL combinations were observed. Carriers of QYr.ufs-2A or QYr.ufs-2D, accompanied by at least one other QTL, exhibited higher resistance levels than lines with a single QTL. The knowledge gained in this study will help wheat breeders to develop cultivars with more diverse combinations and potentially more durable sources of stripe rust resistance.
Highlights
Stripe rust, caused by the fungus Puccinia striiformis Westend. f. sp. tritici (Pst), is a major threat to global wheat (Triticum aestivum L.) production, an industry already under pressure due to increasing demand
The majority of more than 70 wheat stripe rust resistance genes catalogued to date [6] are categorized as all-stage resistance (ASR), most of which are ineffective against current races of Puccinia striiformis f. sp. tritici (Pst)
In this study we selected recombinant inbred line (RIL) from the Yr16DH70 × Palmiet mapping population (MP) that carried different putative combinations of the stripe rust resistance quantitative trait loci (QTL) derived from Cappelle-Desprez
Summary
Stripe (yellow) rust, caused by the fungus Puccinia striiformis Westend. f. sp. tritici (Pst), is a major threat to global wheat (Triticum aestivum L.) production, an industry already under pressure due to increasing demand. Derived from Cappelle-Desprez, the breeding line Yr16DH70, which lacks ASR genes, was selected based on its APR to Pst and adaption to SA wheat growing conditions [14]. A considerable proportion of the stripe rust resistance can be ascribed to QYr.ufs-2A, its effect can be further enhanced through combination with smaller QTL, demonstrated by its significant interactions with the three minor QTL from Yr16DH70. QYr.ufs-6D on the long arm of 6D confers a small effect towards stripe rust resistance in Yr16DH70, contributing a maximum of 7.6% of the phenotypic variation [14]. In this study we selected RILs from the Yr16DH70 × Palmiet MP that carried different putative combinations of the stripe rust resistance QTL derived from Cappelle-Desprez. Traditional phenotypic assessments, along with histological analysis and an estimation of fungal biomass, were employed to gain insight into host-pathogen interactions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
