The 2012 ASHS Annual Conference

Coreopsis and Rudbeckia are two genera of herbaceous ornamentals which have many species native to the United States.  Since 2006 both genera have been priorities for conservation at the Ornamental Plant Germplasm Center (OPGC), a gene bank which is part of the United States Department of Agriculture National Plant Germplasm System.    About 28 species of Coreopsis are native to the U.S. including annual, perennial, subshrub and shrub forms; the OPGC currently conserves over 100 accessions representing 19 species.  Rudbeckia is a genus of 23 species of annual, biennial, and perennial types; currently over 200 accessions of Rudbeckia representing 18 species are being conserved at the OPGC.  To fill gaps in our knowledge about these accessions we are working to characterize wild-collected accessions and compare them to commercially-available cultivars using a set of 53 descriptors which have been selected to identify differences in factors such as growth, leaf and flower morphology, phenology, production, quality, invasiveness, disease, and stress tolerance.  Differences within species have been identified for characteristics such as flower size, flower color, plant height, flowering time, hardiness, and disease resistance.  For example, Rudbeckia floral color and pattern variation is most prevalent in species of the Rudbeckia and Dracopis sections of Rudbeckia  (R. hirta, R. triloba, R. amplexicaulis, and other species) while little variation has been observed in species of the Macrocline section (including R.  laciniata, R. maxima, R. mohrii, and others).  Additionally, variation for disease resistance is primarily noted between the species, although some accessions have been identified which exhibit reduced susceptibility to a disease within a species, for example powdery mildews on R. hirta.  Characterization of accessions may also help identify new commercial possibilities for the floriculture industry.  For example, R. auriculata is a species native only to southeastern U.S. (Georgia, Alabama, and Florida) but has overwintered in Columbus, OH (USDA Plant Hardiness Zone 6a).  Ultimately our goal is to make more information about germplasm conserved at the OPGC available to public and private researchers, thereby making this germplasm more valuable and increasing its utilization in plant breeding and other programs.  Conserved plant material is made freely available in small quantities to researchers and educators worldwide through the Germplasm Resources Information Network (GRIN) database, www.ars-grin.gov; characterization data will also be distributed via the GRIN website.