SUNFLOWER GERMPLASM DIVERSIFICATION AND CHARACTERIZATION UTILIZING WILD SUNFLOWER SPECIES, CYTOGENETICS, AND APPLIED GENOMICS
Location: Sunflower Research
Title: Collection and evaluation of wild perennial Helianthus pumilus achenes for oil concentration and fatty acid composition
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 28, 2011
Publication Date: February 27, 2012
Citation: Seiler, G.J., Gulya Jr, T.J., Fredrick-Marek, L. 2012. Collection and evaluation of wild perennial Helianthus pumilus achenes for oil concentration and fatty acid composition [abstract]. In: 18th International Sunflower Conference Program and Abstracts, Mar del Plata & Barcarce, Argentina, February 27-March 1, 2012. P.175.
The genus Helianthus consists of 51 species and 19 subspecies with 14 annual and 37 perennial species. The narrow genetic base of cultivated sunflower has been broadened by the infusion of genes from the wild species, which have provided a continued source of desirable agronomic traits. There has been an increased interest in using wild species in breeding programs, but there have been concerns about the introgression of low oil content and quality from the wild species. Helianthus pumilus (Dwarf sunflower) is a perennial species with potential genes for oil and fatty acid composition improvement based on its xerophytic habitat. The objective of the study was to undertake an exploration to Colorado and Wyoming, USA to collect achenes from the entire distributional range of H. pumilus and assess the potential of the populations for improving oil content and quality in cultivated sunflower. The sunflower exploration took place from August 7 to August 19, 2005 and covered 5150 kilometers in Colorado and Wyoming. The achene samples were deposited at the USDA-ARS, NPGS, North Central Regional Plant Introduction Station, Ames, Iowa, where they are maintained and distributed. Voucher specimens are maintained at the USDA-ARS wild sunflower species herbarium at Fargo, North Dakota. Heads were collected from 10 to 100 plants within each population and were bulked into a single sample. For each population, a composite sample of 10 randomly sampled achenes was analyzed for fatty acids composition using organic base-catalyzed transesterification of fatty acid methyl esters and capillary gas chromatography. Oil content was determined on a 2-ml achene sample using nuclear magnetic resonance. Achenes of 47 populations were collected and placed in the wild sunflower germplasm collection. The exploration was successful in collecting representative populations from the entire distributional range. The H. pumilus populations had an average oil content of 25.4%, considerably lower than cultivated sunflower, which averages 45% oil. The highest oil content of an H. pumilus population was 29.4%. The linoleic acid concentration approached 75%, much higher than the 55% expected from a semi-arid environment. The combined saturated palmitic and stearic fatty acids in H. pumilus averaged 10.2%, close to cultivated sunflower with an average of 11.5%. The higher concentrations of linoleic acid show that H. pumilus could be a potential source of genes for increasing linoleic acid concentration in traditional sunflower oil grown in southern latitudes. The low oil content of this species can be increased by backcrossing to a high oil cultivar. Further research will be needed to determine the inheritance of the fatty acids and oil content traits.