Linkage Map for Hydrangea macrophylla and Implications for Marker Assisted Selection

Linkage maps are standard tools for agronomic crop improvement using marker-assisted selection strategies. Indirect selection would greatly benefit woody ornamental plant breeding because they have long generation times that can significantly slow progress using conventional breeding strategies.  In woody landscape crops, molecular markers have been used in recent years to evaluate genetic diversity among existing cultivars and germplasm, to revise taxonomy, and for population genetic studies on wild collected plants. This research only requires a small number of loci, especially if SSR markers are being used, and these can be sourced from marker-enriched libraries or cross-amplified from related genera. The same markers can often be used for multiple studies involving a wide range of plants from the same species. Many more markers are needed to make linkage maps or find genetic associations between traits of interest and molecular markers that might be used for indirect selection. The increase in next generation sequencing technology and lowered costs has made sourcing SNP and SSR markers from transcriptome data a viable strategy for minor specialty crops such as woody ornamental plants. Here we present data for Hydrangea macrophylla and Cercis canadensis.