1a.Objectives (from AD-416):
Acquire new germplasm for breeding trees suitable for utility-line applications. Test crossability between new germplasm to determine breeding potentials and advance breeding goals.
1b.Approach (from AD-416):
New germplasm will be acquired from various botanical institutes and commercial nurseries. Wild-collections will be coordinated with the Woody Landscape Plant Crop Germplasm Repository. Material will be planted out for long-term evaluations and for conducting crosses. Controlled pollinations will be combined with molecular tools to verify hybrids and analyze diversity.
New germplasm continues to be collected and planted in coordination with the Woody Landscape Plant Germplasm Repository. Additional breeding lines developed in previous research cycles, including Catalpa, Chitalpa, Magnolia, Nyssa, and Pistacia have been planted out in long term evaluation plots at the U.S. National Arboretum. A large population of Magnolia grandiflora x Magnolia virginia hybrids have been planted which will be screened for foliage quality and persistence, flower size, and compact habit. Screening of Nyssa hybrids for leaf spot resistance, growth habit, and fall color continues. Additional Celtis and Ulmus have been planted in collaboration with arboretum taxonomists. Novel germplasm selections have been incorporated into the permanent collections at the arboretum. These long term evaluation plots will facilitate the screening and selection of diverse smaller, urban adapted trees for planting in height restricted planting areas in cities.