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Title: The vulnerability of US apple (Malus) genetic resources

Author
item Volk, Gayle
item Chao, Chihcheng
item Norelli, John
item BROWN, SUSAN - Cornell University
item Fazio, Gennaro
item PEACE, CAMERON - Washington State University
item MCFERSON, JIM - Washington Tree Fruit Research Commission
item Zhong, Gan-Yuan
item Bretting, Peter

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/27/2015
Publication Date: 6/1/2015
Citation: Volk, G.M., Chao, C.T., Norelli, J.L., Brown, S.K., Fazio, G., Peace, C., McFerson, J., Zhong, G., Bretting, P.K. 2015. The vulnerability of US apple (Malus) genetic resources. Genetic Resources and Crop Evolution. 62(5):765-794. doi:10.1007/s10722-014-0194-2.
DOI: https://doi.org/10.1007/s10722-014-0194-2

Interpretive Summary: This report was written by members of the U.S. Apple Crop Germplasm Committee, a group of scientists and industry representatives that provide data and recommendations on apple genetic resources. This document describes the urgency and extent of vulnerability of apple production to abiotic and biotic threats in the context of U.S. and international apple fruit production and availability of genetic resources to mitigate threats. To assess genetic diversity, the report also includes an overview of the ecogeographical distribution of Malus species. It also provides detailed information about the Malus genetic resources maintained by the National Plant Germplasm System at the Plant Genetic Resources Unit in Geneva, NY. This collection currently has 5226 trees in the field and 1508 seed accessions representing M. × domestica, 33 Malus species and 15 hybrid species. The crop vulnerability status of apple in the U.S. was ranked as moderate because there are relatively few breeders, a limited number of cultivars in production, threats of new diseases, pests, and changing climate combined with industry challenges and consumer demands.

Technical Abstract: Apple is one of the top three U.S. fruit crops in production and value. Apple production has high costs for land, labor and inputs, and orchards are a long-term commitment. Production is dominated by only a few apple scion cultivars and rootstocks, which increases susceptibility to dynamic external threats. Apple crop wild relatives, including progenitor species M. sieversii, M. orientalis, M. sylvestris, and M. prunifolia, as well as more than twenty other readily hybridized species, have a wide range of biotic and abiotic stress resistances as well as desirable productivity and fruit quality attributes. However, access to wild materials is limited and wild Malus throughout the world is at risk of loss due to human encroachment and changing climatic patterns. The USDA-ARS National Plant Germplasm System (NPGS) Malus collection, maintained by the Plant Genetic Resources Unit in Geneva, NY, U.S. is among the largest collections of cultivated apple and related Malus species in the world. The collection currently has 5226 trees in the field and 1508 seed accessions representing M. × domestica, 33 Malus species and 15 hybrid species. The permanent, grafted collection has 3070 accessions that are represented by a core collection of 258 individuals. Many wild species accessions are represented as single seedlings (non-grafted). The crop vulnerability status of apple in the U.S. is moderate because there are relatively few breeders, a limited number of cultivars in production, threats of new diseases, pests, and changing climate combined with industry challenges and consumer demands.