Quantitative trait loci for resistance against Yellow rust in two wheat-derived recombinant inbred line populations

Abstract

Yellow rust, which is a major disease in areas where cool temperatures prevail, can strongly influence grain yield. To control this disease, breeders have extensively used major specific resistance genes. Unfortunately this kind of resistance is rapidly lost due to pathogen adaptation. More-durable resistance against yellow rust can be achieved using quantitative resistance derived from cultivars with well-established durable resistance. The winter wheat Camp Remy has maintained a high level of resistance for over 20 years. In order to map quantitative trait loci (QTLs) for durable yellow rust resistance, we analysed a set of 98 F(8) recombinant inbred (RI) lines derived from the cross Camp RemyxMichigan Amber. We also mapped QTLs for adult resistance to yellow rust using the International Triticae Mapping Initiative RI population (114 lines derived from the cross Opata85xsynthetic hexaploid). Two and five QTLs, respectively, were identified from these two populations. This work has highlighted the importance of the centromeric region of chromosome 2B and the telomeric regions of chromosomes 2AL and 7DS in durable yellow rust resistance. The same chromosomal regions are also implicated in resistance to other pathogens.

Identification of adult plant resistance to stripe rust in the wheat cultivar Cappelle-Desprez

“…Mallard et al (2005) attributed between 20 and 40% of the phenotypic variance to QYr.inra-2AL, which is comparable to the phenotypic variance explained by QYr.ufs-2A. In the study of Boukhatem et al (2002), QYR2 accounted for only 15.4% of the phenotypic variation. Bariana et al (2010) identified an APR QTL proximal to the region defining QYr.…”

“…While up to 75.2% of the variation seen for RT was explained by the QTL identified, only 60.4% of the variation seen for LAI was explained. Although heavy selection pressure for adult plant stripe rust resistance was imposed during the development and selection of Yr16DH70, minor QTL and QTL where expression is heavily influenced by environmental factors (Boukhatem et al 2002), may not have been retained in Yr16DH70. This may account for the consistently, but marginally higher disease rating obtained for Yr16DH70 compared to Cappelle-Desprez in each year of testing.…”

“…This does not exclude QYr.ufs-2A from representing an adult plant race-specific resistance locus which has not as yet been overcome by South African pathotypes. Boukhatem et al (2002) detected an APR QTL (QYR2) in the cv. Camp Rémy, a descendant of Cappelle-Desprez which is also described as having durable stripe rust resistance.…”

Association Analysis of Historical Bread Wheat Germplasm Using Additive Genetic Covariance of Relatives and Population Structure

“…Some significant DArT markers proved to be associated with known YR resistance genes, such as Yr24 at 1B, which is allelic to Yr26 and closely linked to barc187 (Li et al 2006) (Figure 2a). Boukhatem et al (2002) identified two major QTL for durable YR resistance on chromosome 2B, of which one was present in Opata 85 and mapped near the SSR marker gwm410. This marker is also present in LDb3 with wPt7757, which is significantly associated with YR ( Figure 2b, Table 4).…”

“…Yr30, at 3BS, has been reported to be linked to Sr2 and Lr27, and to SSR marker gwm533 (Spielmeyer et al 2003), and may be marked by wPt0995 and other DArT markers at LDb3 (Figure 2c) (it is present in Opata 85 and Pavon F76, included in this study). Singh et al (2000) and Boukhatem et al (2002) identified a region on chromosome 3DS associated with YR in Opata 85, which could have been identified by wPt1336 and wP19401.…”