Using a limited mapping strategy to identify major QTLs for resistance to grapevine powdery mildew (Erysiphe necator) and their use in marker-assisted breeding

Abstract

A limited genetic mapping strategy based on simple sequence repeat (SSR) marker data was used with five grape populations segregating for powdery mildew (Erysiphe necator) resistance in an effort to develop genetic markers from multiple sources and enable the pyramiding of resistance loci. Three populations derived their resistance from Muscadinia rotundifolia ‘Magnolia’. The first population (06708) had 97 progeny and was screened with 137 SSR markers from seven chromosomes (4, 7, 9, 12, 13, 15, and 18) that have been reported to be associated with powdery or downy mildew resistance. A genetic map was constructed using the pseudo-testcross strategy and QTL analysis was carried out. Only markers from chromosome 13 and 18 were mapped in the second (04327) and third (06712) populations, which had 47 and 80 progeny, respectively. Significant QTLs for powdery mildew resistance with overlapping genomic regions were identified for different tissue types (leaf, stem, rachis, and berry) on chromosome 18, which distinguishes the resistance in ‘Magnolia’ from that present in other accessions of M. rotundifolia and controlled by the Run1 gene on chromosome 12. The ‘Magnolia’ resistance locus was termed as Run2.1. Powdery mildew resistance was also mapped in a fourth population (08391), which had 255 progeny and resistance from M. rotundifolia ‘Trayshed’. A locus accounting for 50% of the phenotypic variation mapped to chromosome 18 and was named Run2.2. This locus overlapped the region found in the ‘Magnolia’-based populations, but the allele sizes of the flanking markers were different. ‘Trayshed’ and ‘Magnolia’ shared at least one allele for 68% of the tested markers, but alleles of the other 32% of the markers were not shared indicating that the two M. rotundifolia selections were very different. The last population, 08306 with 42 progeny, derived its resistance from a selection Vitis romanetii C166-043. Genetic mapping discovered a major powdery mildew resistance locus termed Ren4 on chromosome 18, which explained 70% of the phenotypic variation in the same region of chromosome 18 found in the two M. rotundifolia resistant accessions. The mapping results indicate that powdery mildew resistance genes from different backgrounds reside on chromosome 18, and that genetic markers can be used as a powerful tool to pyramid these loci and other powdery mildew resistance loci into a single line.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-010-1511-6) contains supplementary material, which is available to authorized users.

Detection of downy and powdery mildew resistance QTL in a ‘Regent’ × ‘RedGlobe’ population

“…One region of distortion that stood out was chromosome 15 where all 13 markers showed significant segregation distortion as previously reported for 'Regent' in this region by Welter et al (2007). Riaz et al (2011) also reported segregation distortion for this chromosome in the '06708' population derived from 'Magnolia' (M. rotundifolia). This chromosome appears to be problematic as Lowe and Walker (2006) also could not construct a linkage group 15 for 'Riparia Gloire' (V. riparia), while the map for the other parent, 'Ramsey' (V. champinii), contained four markers spanning a region of 28 cM.…”

“…This is higher than that reported by Troggio et al (2007) and Grando et al (2003), but lower than the 40 % reported by Riaz et al (2011). One region of distortion that stood out was chromosome 15 where all 13 markers showed significant segregation distortion as previously reported for 'Regent' in this region by Welter et al (2007).…”

“…The Ren1 locus was identified on chromosome 13 of V. vinifera 'Kishmish vatkana' by Hoffmann et al (2008). Riaz et al (2011) identified several resistance loci on chromosome 18 in Euphytica (2014) (Fischer et al 2004;Akkurt et al 2007;Welter et al 2007) and confirmed in 'Villard Blanc' ). Blanc et al (2012) identified and mapped the Ren5 locus to chromosome 14 of Muscadinia rotundifolia cv.…”

“…It is thought that the resistance to the pathogen co-evolved along with the pathogen, which is endemic to North America. Riaz et al (2011) suggested that the resistance to P. viticola found in some Asian species like V. amurensis could have evolved as resistance to P. cissii and P. amurensis, which are endemic to Asia. Several breeding programmes strive to transfer resistance identified in other Vitis species to V. vinifera.…”

Breeding of fungal resistant varieties derived from Grüner Veltliner by chromosomal selection

“…For Chromosome 18 the segregation of alleles could easily be defined with five SSR markers. We only find relevance for OIV 94 but other papers show influence in berry weight or size [23] and dependance on the population resistance against Plasmopara [11] or Erysiphe [26].…”