2006 Annual Report 4d.Progress report. This report serves to document research conducted under a specific cooperative agreement between ARS and University of Missouri. Additional details of research can be found in the report for the parent project 5358-21000-036-00D, Physiology, Biochemistry, and Genetic Improvement of Small Fruit Crops. Dr. Andrew Thomas and collaborators conducted the following research towards the agreements objectives: Since 1999, researchers at the University of Missouri’s Southwest Research Center at Mt. Vernon, and the State Fruit Experiment Station of Missouri State University at Mountain Grove, have been developing and studying a collection of improved elderberry (Sambucus nigra subsp. canadensis) cultivars. We presently have more than 60 cultivars and selections under evaluation at both locations and continue to search for superior germplasm. Grant #1 allowed us to diligently screen and evaluate 35 initial cultivars for their horticultural potential. We were amazed at the phenological diversity within these selections, as well as their varying yield potentials. Grant #2 permitted us to plant scientifically-based experiments at three diverse locations to elucidate true horticultural differences and to allow us to recommend superior cultivars for release to the public. Several scientific publications (see below) are and will be a direct result of these two grants. More than 500 elderberry plants were propagated, grown, and evaluated for these studies. Once the plantings were installed, they became an excellent resource for additional horticultural studies. For example, we now have a $75,496 grant proposal being considered (with excellent chance for funding) by Land O’Lakes for a long-term soil fertility and plant nutrition study. Without the initial startup funding from USDA, this terrific expansion of the project would not have been possible. We continue to document the tremendous genetic diversity and horticultural potential among the 60 elderberry cultivars under evaluation. Two cultivars, ‘Gordon B’ and ‘Wyldewood 1’ have performed so well in our trials that we are currently negotiating with their owners to publish and release the cultivars to the public. Horticultural data on growth, vigor, hardiness, cane production, and disease and insect susceptibility continue to be collected, along with fruiting characteristics such as panicle size and number, berry size and number, fruit quality, flavor, color, skin characteristics, and ripening period. We have also been working with the USDA South Central Agricultural Research Laboratory at Lane, OK to quantify the fruit and juice characteristics of each cultivar. Our studies have also expanded into the medicinal aspects of elderberry fruit and non-fruit tissues, which appear to be equally diverse among the various cultivars.