Pear (Pyrus spp.) is one of the most important edible fruits belonging to the family Rosaceae. DNA markers, molecular genetics and genomics, and molecular breeding of pear have greatly progressed over the last few decades. The development of reliable DNA markers, such as simple sequence repeats and single nucleotide polymorphisms, has allowed DNA profiling of pear accessions, assessment of the genetic diversity within pear species, and analyses of phylogenetic relationships among pear species. Reference genetic linkage maps and genome-wide molecular markers have enabled practical marker-assisted selection for resistance to black spot and/or pear scab diseases, self-compatibility, harvest time, and fruit skin color in Japanese pear breeding programs. Molecular breeding has been shown to more than triple the selection efficiency of practical breeding compared with conventional breeding. Furthermore, breeding programs using two novel genomics-based approaches—genome-wide association studies and genomic selection—focusing on fruit quality and texture, and quantitative traits for breeding, are in progress. Co-linearity and functional synteny have been identified between pear and apple (Malus × domestica Borkh), and have been used to efficiently predict the function of a gene of interest and develop selection markers in related species.

梨（梨spp。）是蔷薇科最重要的食用水果之一。在过去的几十年中，梨的DNA标记，分子遗传学和基因组学以及分子育种取得了长足的进步。可靠的DNA标记的开发，例如简单的序列重复和单核苷酸多态性，已使梨种的DNA谱分析，评估梨种内的遗传多样性以及分析梨种间的系统发生关系。参考遗传连锁图谱和全基因组分子标记物已经使日本梨育种计划中实用的标记物辅助选择能够抵抗黑斑病和/或梨疮ab病，自我适应性，收获时间和果皮颜色。与常规育种相比，分子育种已显示出实用育种选择效率的三倍以上。此外，采用两种基于基因组学的新颖方法（全基因组关联研究和基因组选择）的育种计划正在着手进行，其重点是水果的质量和质地以及育种的定量性状。梨和苹果之间已经确定了共线性和功能同构（海棠（Malus × domestica Borkh），并已被用于有效预测目标基因的功能并在相关物种中开发选择标记。