Disease-resistant apple cultivars developed from the apple breeding program at the University of Illinois

Title from caption.Mode of access: Internet

Apple structural genomics

Review di genomica strutturale del mel

A multi-population consensus genetic map reveals inconsistent marker order among maps likely attributed to structural variations in the apple genome

Genetic maps serve as frameworks for determining the genetic architecture of quantitative traits, assessing structure of a genome, as well as aid in pursuing association mapping and comparative genetic studies. In this study, a dense genetic map was constructed using a high-throughput 1,536 EST-derived SNP GoldenGate genotyping platform and a global consensus map established by combining the new genetic map with four existing reliable genetic maps of apple. The consensus map identified markers with both major and minor conflicts in positioning across all five maps. These major inconsistencies among marker positions were attributed either to structural variations within the apple genome, or among mapping populations, or genotyping technical errors. These also highlighted problems in assembly and anchorage of the reference draft apple genome sequence in regions with known segmental duplications. Markers common across all five apple genetic maps resulted in successful positioning of 2875 markers, consisting of 2033 SNPs and 843 SSRs as well as other specific markers, on the global consensus map. These markers were distributed across all 17 linkage groups, with an average of 169633 marker per linkage group and with an average distance of 0.7060.14 cM between markers. The total length of the consensus map was 1991.38 cM with an average length of 117.14624.43 cM per linkage group. A total of 569 SNPs were mapped onto the genetic map, consisting of 140 recombinant individuals, from our recently developed apple Oligonucleotide pool assays (OPA). The new functional SNPs, along with the dense consensus genetic map, will be useful for high resolution QTL mapping of important traits in apple and for pursuing comparative genetic studies in Rosaceae

Construction of a high-density Simple Sequence Repeat consensus genetic map for pear (Pyrus spp.).

As an important fruit crop that is widely grown commercially in temperate regions of the world, pear (Pyrus) is a target for pursuing efficient breeding strategies. Construction of a reliable and dense genetic linkage map is critical for undertakingmarker-assisted breeding. In this study, a population of 56 F1 seedlings of ‘Bayuehong’בDangshansuli’ was used to construct a high-density simple sequence repeat (SSR)-based genetic linkage map