Abstract
Key message This consensus map of stem rust genes, QTLs, and molecular markers will facilitate the identification of new resistance genes and provide a resource of in formation for development of new markers for breeding wheat varieties resistant to Ug99. The global effort to identify new sources of resistance to wheat stem rust, caused by Puccinia graminis f. sp. tritici race group Ug99 has resulted in numerous studies reporting both qualitative genes and quantitative trait loci. The purpose of our study was to assemble all available information on loci associated with stem rust resistance from 21 recent studies on Triticum aestivum L. (bread wheat) and Triticum turgidum subsp. durum desf. (durum wheat). The software LPmerge was used to construct a stem rust resistance loci consensus wheat map with 1,433 markers incorporating Single Nucleotide Polymorphism, Diversity Arrays Technology, Genotyping-by-Sequencing as well as Simple Sequence Repeat marker information. Most of the markers associated with stem rust resistance have been identified in more than one population. Several loci identified in these populations map to the same regions with known Sr genes including Sr2, SrND643, Sr25 and Sr57 (Lr34/Yr18/Pm38), while other significant markers were located in chromosome regions where no Sr genes have been previously reported. This consensus map provides a comprehensive source of information on 141 stem rust resistance loci conferring resistance to stem rust Ug99 as well as linked markers for use in marker-assisted selection.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-014-2326-7) contains supplementary material, which is available to authorized users.
Highlights
Wheat stem rust caused by the pathogen Puccinia graminis Pers. f. sp. tritici Eriks. and E
With a global average distance of 2.7 cM between markers, the maximum average distance between markers is observed on chromosome 5D (16 markers) with 7.6 cM and the minimum average distance between markers is observed on chromosome 3B
Resistance gene and quantitative trait loci (QTL) maps and gene cloning information from 21 studies and one personal communication (Table 1) involving 24 mapping populations, three association panels, and two BC2 populations were concatenated to construct a map for stem rust resistance loci (Fig. 1)
Summary
Wheat stem rust caused by the pathogen Puccinia graminis Pers. f. sp. tritici Eriks. and E. Adult plant resistance to stem rust in wheat is a complex trait conferred by quantitative trait loci (QTL). This type of resistance can be more durable than single gene resistance due to race non-specificity of the resistance genes involved. A total of five numerically designated wheat stem rust resistance genes confer quantitative APR: Sr2, Sr55 (Lr67/Yr46/ Pm46), Sr56, Sr57 (Lr34/Yr18/Pm38), and Sr58 (Lr46/ Yr29/Pm39). Several recent studies have identified numerous QTL associated with wheat stem rust resistance in diverse germplasm (Bansal et al 2008; Bhavani et al 2011; Crossa et al 2007; Kaur et al 2009; Njau et al 2013; Rouse et al 2014; Singh et al 2013a, b, c; Yu et al 2011, 2012). The consensus map contains Diversity Arrays Technology (DArT), Single Nucleotide Polymorphism (SNP), Genotyping-by-Sequencing (GBS) and Simple Sequence Repeat (SSR) markers to facilitate cross-referencing markers and Ug99 resistance loci with other maps
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