摘要 : A limited genetic mapping strategy based on simple sequence repeat (SSR) marker data was used with five grape populations segregating for powdery mildew (<i>Erysiphe necator</i>) resistance in an effort to develop genetic markers ... 展开 A limited genetic mapping strategy based on simple sequence repeat (SSR) marker data was used with five grape populations segregating for powdery mildew (<i>Erysiphe necator</i>) resistance in an effort to develop genetic markers from multiple sources and enable the pyramiding of resistance loci. Three populations derived their resistance from <i>Muscadinia rotundifolia</i> '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 <i>M. rotundifolia</i> and controlled by the <i>Run1</i> gene on chromosome 12. The 'Magnolia' resistance locus was termed as <i>Run2.1</i>. Powdery mildew resistance was also mapped in a fourth population (08391), which had 255 progeny and resistance from <i>M. rotundifolia</i> 'Trayshed'. A locus accounting for 50% of the phenotypic variation mapped to chromosome 18 and was named <i>Run2.2</i>. 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 <i>M. rotundifolia</i> selections were very different. The last population, 08306 with 42 progeny, derived its resistance from a selection <i>Vitis romanetii</i> C166-043. Genetic mapping discovered a major powdery mildew resistance locus termed <i>Ren4</i> on chromosome 18, which explained 70% of the phenotypic variation in the same region of chromosome 18 found in the two <i>M. rotundifolia</i> 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. 收起