Submitted to: Sunflower International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: February 24, 2012
Publication Date: March 1, 2012
Citation: Marek, L., Block, C.C., Gardner, C.A. 2012. 2012 Update: New Sunflower Genetic Resources in the US National Sunflower Collection and Potential Use for Crop Improvement. Sunflower International Conference Proceedings. Available: http://www.asagir.org.ar/asagir2008/archivos_congreso/2012 Update New Sunflower Genetic Resources in the US National Sunflower Collection and Potential Use for Crop Improvement.doc. Technical Abstract: The Helianthus L. germplasm collection in the National Plant Germplasm System of the United States is held at the North Central Regional Plant Introduction Station in Ames, IA and administered by the USDA-ARS Plant Introduction Research Unit in cooperation with the Agricultural Experiment Station at Iowa State University. The sunflower collection is composed of accessions of the domesticated species Helianthus annuus and its wild relative taxa along with associated passport and other information. Sunflower germplasm is acquired, regenerated, characterized and distributed to conduct and support research and education. We provide a summary of regeneration protocols, describe new germplasm received in the past four years and provide an example of wild sunflower disease resistance evaluation taking place in Ames. Regenerations take place under controlled conditions so that the genetic character of received material is maintained as closely as possible. New material is obtained by donation, by receipt of material with expired intellectual property right protection and by active collection. The wild Helianthus collection is being systematically evaluated at Ames for resistance to Sclerotinia stalk rot using a sub-surface soil application of Sclerotinia-infested millet. Promising material is further evaluated in field trials to confirm resistance. Since 2008, three Plant Exchange Office (National Plant Genetic Resources Laboratory, USDA-ARS) sponsored collection trips for wild sunflower have added 160 accessions, sampling wild populations of 202 different taxa, two of which were not previously available for distribution. Additional accessions have been received by donation and after expiration of intellectual property right protection. Overall, 91% of the sunflower collection is available for distribution. Of accessions evaluated for Sclerotinia stalk rot in Ames, the best sources of resistance among annual species occur within H. argophyllus, H. debilis, H. praecox and H. agrestis, with little resistance found in wild H. annuus. The majority of accessions from the eight perennial taxa screened to date have shown superior resistance with 90-100% of the plants fully resistant to Sclerotinia stalk rot. The USDA sunflower collection provides a unique sampling of genetic diversity within the wild sunflower taxa as well as containing accessions of domesticated H. annuus. Wild sunflower accessions identified as resistant to Sclerotinia stalk rot during greenhouse-based screening in Ames have the potential to provide useful traits to improve cultivated sunflower. The USDA sunflower collection is freely available to scientists and educators world-wide for research, crop improvement, product development and educational use.