2010 Annual Report 1a.Objectives (from AD-416) The overall objective of this project is to breed, evaluate, select, and release improved landscape trees and shrubs that are disease and pest resistant, tolerant of environmental stresses, are not invasive, and have superior ornamental value. This objective is achieved by genetically characterizing and evaluating the horticultural merit and stress resistance contained in germplasm and advanced selections of Cercis, Lagerstroemia, and Prunus (primary genera), as well as historical or exploratory genera such as Corylopsis, Deutzia, Ilex, Gaylussacia, Syringa, and Viburnum (secondary genera); developing new or improved genetic marker systems for assessing genetic diversity and accelerating genetic improvement of these genera; incorporating improved disease and stress resistance and ornamental traits into this germplasm using traditional and new breeding methodologies; and transferring superior landscape plant cultivars and germplasm to end users. This research will result in new cultivars of landscape trees and shrubs that have value to the nursery and landscape industries; germplasm that has been evaluated or enhanced for various traits; and technology on molecular markers, gene manipulation, and wide hybridization. 1b.Approach (from AD-416) Conduct comprehensive breeding programs by genetically characterizing and evaluating the horticultural merit and stress resistance contained in germplasm and advanced selections of Cercis, Lagerstroemia, and Prunus (primary genera), as well as historical or exploratory genera such as Corylopsis, Deutzia, Ilex, Gaylussacia, Syringa, and Viburnum (secondary genera); developing new or improved genetic marker systems for assessing genetic diversity and accelerating genetic improvement of these genera; incorporating improved disease and stress resistance and ornamental traits into this germplasm using traditional and new breeding methodologies; and transferring superior landscape plant cultivars and germplasm to end users. 3.Progress Report The redbud (Cercis) reference collection consisting of all known cultivars was finished, and will be used as a source of germplasm and for trait comparisons in the redbud breeding program. Selections of redbud and Corylopsis were propagated for further evaluation. Controlled pollinations were made in Corylopsis, redbud, and flowering cherry, and seeds were harvested and sown. Open-pollinated seeds from box huckleberry, which represent significant recombination in this species, were collected from diverse accessions. Tetraploid plants of redbud, flowering cherry, and catalpa were created, which will be used for breeding when they reach flowering age. Review Publications Ma, H., Olsen, R., Pooler, M, Kramer, Matthew. 2009. Evaluation of Flowering Cherry Species, Hybrids, and Cultivars Using Simple Sequence Repeat Markers. Journal of the American Society for Horticultural Science. 134:435-444.