Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/8/2008
Publication Date: 5/1/2009
Citation: Richards, C.M., Volk, G.M., Reeves, P.A., Reilley, A., Henk, A.D., Forsline, P.L., Aldwinckle, H. 2009. Selection of stratified core sets representing wild apple (Malus sieversii). Journal of the American Society for Horticultural Science. 134:228-235.
Interpretive Summary: The wild apple species Malus sieversii is found in the mountainous regions of Central Asia. This species is believed to a primary progenitor species to the cultivated apple (Malus Xdomestica). The National Plant Germplasm Collection in Geneva, NY maintains more than 1000 M. sieversii trees that have been grown from seed collected in Kazakhstan and Kyrgyzstan. In this report, we propose a set of 35 individuals that complements the previously published subsets of individuals collected from two specific sites. Combined, the 112 individuals included in the three subsets capture most of the genetic and phenotypic diversity of the M. sieversii collection. These core collection sets capture the maximum level of diversity with a minimum number of individuals.
Technical Abstract: In this report, we estimate the minimum core size necessary to maximally represent of the USDA’s National Plant Germplasm System M. sieversii collection. We have identified a subset of M. sieversii individuals that complements the previously published core subsets for two collection sites within Kazakhstan. We compared the size and composition of this complementary subset with a core set composed without restrictions. Because the genetic structure of M. sieversii has been estimated (Richards et al. 2008), we were able to identify the origin of individuals within this core set with respect to their geographic location and genetic lineage. In addition, the core set is structured in a way that samples all the major genetic lineages identified in this collection. The resulting panel of genotypes captures a broad range of phenotypic and molecular variation throughout Kazakhstan. These samples will provide a manageable entry point into the larger collection and will be critical in developing a long-term strategy for ex situ wild Malus conservation.