2007 Annual Report 1a.Objectives (from AD-416) Produce clonal hemlock propagules of previously generated interspecific Tsuga hybrids and of T. chinensis seedlings of documented wild-collected germplasm accessions for further evaluation of adelgid tolerance and growth characteristics in multiple environments. Evaluation of the growth and resistance to Hemlock Woolly Adelgid (HWA) of a replicated field trial of documented wild-collected T. chinensis germplasm and hybrid-crosses between T. chinensis and T. caroliniana. 1b.Approach (from AD-416) Cuttings will be taken from healthy and vigorously growing individuals of the species and hybrids including T. chinensis x T. caroliniana, T. caroliniana x T. chinensis, T. chinensis x. T. diversifolia, T. chinensis x T. sieboldii, T. canadensis and T. chinensis. Rooting will be attempted in winter and/or spring/summer with dormant and actively growing materials and depending on size of parent plant. Rooted plants will be grown for 2- 3 years in a shaded polyhouse, and will be utilized for greenhouse or growth chamber inoculation with HWA. Field inoculation with HWA of hemlock hybrids and species will be initiated in year one with our cooperating entomologist. Plants will be heavily infested to screen out poorly to moderately resistant genotypes and identify most tolerant genotypes. 3.Progress Report Woolly adelgid resistant hemlock breeding This report documents research conducted under a reimbursable agreement between ARS and the U.S. Forest Service. This research was carried out in collaboration with U.S. Forest Service Center for Forest Health Research partners and with assistance from the U.S. National Arboretum Gardens Unit and Germplasm Units. Additional details of the research can be found in the report for the parent project 1230-21000-043-00D, "Genetic Improvement of Landscape Trees for Superior Pest Resistance." Interspecific hemlock hybrids and species were field re-inoculated with hemlock woolly adelgid in spring 2007 and data collected on infestation and reproduction of the adelgids through fall 2007 as is data on size, cone-bearing and fertility of hybrids. Propagation experiments of interspecific hemlock hybrids and species were initiated in February and July 2007, and rooting evaluation of over 2000 cuttings has begun. This research is part of Component II of National Program 301 (Genome characterization and genetic improvement); and is under ARS Strategic Plan Goal 1, Performance measure 1.2.8 and Goal 3, Performance measure 3.2.4. This project is being monitored by emails, site visits and phone calls.