Evaluation, Characterization, and Identification of Woody Landscape Plants

The objectives of the Woody Landscape Plants Germplasm Repository (WLPGR) program at the US National Arboretum (USNA) can be divided into a repository component and a research component. Repository components are to introduce, maintain, and distribute diverse and wild-origin genetic resources of trees and shrubs for landscape use. Research components include evaluation, characterization, and identification of germplasm. Seed germination in Styrax japonicus has been studied. Seeds require one month of warm stratification followed by two to three months of cold stratification to achieve greater than 85% germination within one month of sowing. Characterization of Pinus sylvestris var. sylvestriformis by cpDNA and SSR revealed that this taxon may be the hybrid, P. densiflora x P. sylvestris, rather than P. sylvestris var. sylvestriformis. Molecular markers including randomly amplified polymorphic DNA (RAPD) and the single nucleotide polymorphisms (SNP) have also been utilized to study Ilex x wandoensis, Prunus taxa native to Korea including P. yedoensis from wild populations and cultivated sources, and Corylopsis including C. coreana, C. glabrescens and C. gotoana. A sequence-characterized amplified region (SCAR) marker differentiated a subgroup of seedlings from a natural cross of a white-berry form of Ardisia crenata with variegated foliage from a form of A. crenata with red berries.