Vulnerability of pear (Pyrus) genetic resources in the U.S.

Authors: Waite, Jessica; Gottschalk, Christopher; Reinhold Aboosaie, Lauri; Bassil, Nahla; Volk, Gayle; POSTMAN, JOSEPH - Retired ARS Employee; ELKINS, RACHEL - Retired Non ARS Employee; BELL, RICHARD - Retired ARS Employee

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2024
Publication Date: 5/19/2024
Citation: Waite, J.M., Gottschalk, C.C., Reinhold Aboosaie, L.A., Bassil, N.V., Volk, G.M., Postman, J., Elkins, R., Bell, R. 2024. Vulnerability of pear (Pyrus) genetic resources in the U.S. Genetic Resources and Crop Evolution. https://doi.org/10.1007/s10722-024-01990-9.
DOI: https://doi.org/10.1007/s10722-024-01990-9

Interpretive Summary: Pears (Pyrus) are an important part of national agriculture and consumer diets. The pear industry is declining, in part due to few options for production. Here we report on the genetic similarities between pear cultivars and rootstocks that are currently used for growing and production, and describe the targets and goals of national and international breeding programs to increase genetic diversity and options for growers. Threats to pear crops, both biotic (for example bacteria, insects, and viruses) and abiotic (for example heat and cold extremes), and production and marketing vulnerabilities are presented in detail. We report the status of genetic resources within the U.S., especially the National Clonal Germplasm Repository pear collection, as well as genomics tools and resources for pear research and breeding. We additionally summarize international resources, tools, and efforts to maintain wild populations. Finally, we present prospectives on needs for covering genetic gaps, phenotypic and genomic characterization of pear germplasm, and important future areas of research.

Technical Abstract: Pears (Pyrus) represent an important part of consumer diets, and have the fourth highest production of non-citrus fruits, measured by fresh weight, in the U.S. They are maintained clonally and grown as composite plants, consisting of a scion (fruit bearing) variety grafted onto a rootstock variety. The vast majority, up to 98%, of production relies on only a few scion and rootstock cultivars, leaving the standing crop vulnerable to threats. Pears are faced with a wide range of biotic and abiotic threats and production vulnerabilities, which can be limited by integrating resistance and horticultural traits from wild and cultivated materials around the world. The National Clonal Germplasm Repository (NCGR), part of the USDA-ARS National Plant Germplasm System (NPGS), maintains a large Pyrus collection from across the globe, consisting of 2793 Pyrus accessions, from 37 species. The collection represents an important resource for preservation, research, and breeding efforts for pears. The crop vulnerability status of pears in the U.S. is currently moderate to high, with few fruit and rootstock varieties in production and increasing threats and challenges. However, breeding and preservation efforts, along with genetic, crop protection and production research are actively targeting these needs.