Pear Germplasm Needs and Conservation

Abstract

Pear (Pyrus) species are sources of food, drink, landscape trees, and rootstocks. Different Pyrus species possess varied genetic traits that render them useful for diverse purposes. Pear genebanks preserve cultivars, or unique genotypes, as grafted trees. They also store seedlots and seedling populations that may represent pear wild relative species. Seed and seedling collections usually represent species populations from distinct geographic locations rather than unique genotypes. In the USA, the USDA Agricultural Research Service’s National Plant Germplasm System maintains a genebank in Corvallis, Oregon, representing world diversity for Pyrus that includes more than 2500 unique clones or seedlots. Other pear genebanks around the world tend to be more specialized, focusing on accessions native to the region or in support of focused breeding programs. Molecular techniques and genetic markers have become valuable tools for pear genebank management. Various types of molecular markers can be used to assess genetic diversity, identify gaps in germplasm collections, and help detect redundancy and confirm synonymy. Microsatellite, or simple sequence repeat (SSR), markers, and chloroplast-derived markers are commonly used to accomplish these tasks. Markers can also be used for pedigree analysis, which may either confirm or detect anomalies in pedigrees of genebank accessions. Advances in breeding, developing genetic markers, and identifying major genes in pear cannot be accomplished without access to diverse living collections of Pyrus germplasm.