Linkage Mapping in Pear

Abstract

The past three decades have witnessed the development of genetic linkage maps and use of DNA markers in mapping agronomic traits in many crops. In comparison with other plants, linkage mapping in pear has been initiated rather late, not until the year 2001. Pear is characterized by a typical self-incompatibility, and it has a long generation cycle. Therefore, genetic maps have been constructed using F1 populations. This may lead to the development of linkage maps of lower resolutions due to the lack of sufficient genetic variations. Fortunately, the development of next-generation sequencing technology has allowed for detection of high-quality genome-wide DNA markers, such as simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs), in larger size populations, thus greatly improving the quality of genetic linkage maps. Overall, linkage maps are highly useful for dissecting complex agronomic traits, and for identifying either quantitative trait loci (QTL) or key genes regulating a target trait of interest. Furthermore, they contribute to efforts to pursue marker-assisted breeding (MAB) in pear.