Evaluation, characterization, and identification of woody landscape plants

Abstract

The objectives of the Woody Landscape Plants Germplasm Repository (WLPGR) program at the US National Arboretum (USNA) are composed of two parts, repository activities and a research component. Repository activities 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 and over-wintering survival problems in Styrax japonicus have 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. The viability of Ardisia crenata seeds, which are recalcitrant and viable for about 2 to 4 weeks, can be extended to 15 weeks. Identification of Acer griseum germplasm and of an interspecific hybrid was investigated using RAPD. Characterization of Pinus sylvestris var. sylvestriformis by cpDNA and SSR revealed that the hybrid formula, P. densiflora H P. sylvestris may be appropriate, rather than P. sylvestris var. sylvestriformis. Molecular markers including RAPD, ISSR, and SNP have also been utilized to study Ilex x wandoensis, Prunus including P. yedoensis from wild populations and cultivated sources, and Corylopsis including C. coreana, C. glabrescens, and C. gotoana. A SCAR marker differentiated a subgroup of seedlings from a natural cross of a white berry form of A. crenata with variegated foliage form of A. crenata with red berries. For Camellia, SCAR markers for cold hardiness are being developed to screen progeny of crosses between cold hardy and non-cold hardy lines.