Submitted to: International Conference on Industrial Crops and Rural Development Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 12/31/2004
Publication Date: 9/17/2005
Citation: Seiler, G.J. 2005. Wild annual Helianthus anomalus and H. deserticola as potential sources of improved oil content and quality in cultivated sunflower [abstract]. International Conference on Industrial Crops and Rural Development, September 17-21, 2005, Murcia, Spain. p. 47.
Technical Abstract: The genus Helianthus is composed 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 anomalus and H. deserticola are excellent candidates for oil improvement based on their desert environment. Unfortunately, due to the demand for achenes of these species and the difficulties of regenerating the original populations, achenes have not been available for research for almost 20 years. The objective of the study was to undertake an exploration to the desert southwest USA to collect achenes of the two desert species and to assess their potential for improving oil content and quality in cultivated sunflower. The sunflower exploration took place from September 16 to September 23, 2000. The exploration covered 4000 kilometers in three states, Utah, Arizona, and Nevada. 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 20 achenes was analyzed for fatty acids 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 (NMR). The achene samples were deposited at the USDA-ARS North Central Regional Plant Introduction Station, Ames, IA, where they are maintained and distributed. It had been 20 years since 25 known locations of the two species were last visited. For unexplained reasons, only three populations had plants with achenes for collection in 2000. It had been extremely dry in most of the areas explored, with no evidence of the species being present in the fragile sandy habitats. The H. deserticola population had a typical oil concentration of 330 g/kg while the populations of H. anomalus had very high oil contents of 430 and 460 g/kg, respectively, the highest ever observed in any wild species. The fatty acid profiles of H. anomalus had a high linoleic acid concentration for a desert environment, approaching 700 g/kg. A linoleic acid concentration of 540 g/kg in H. deserticola was more typical of the expected concentration in a desert environment. The combined saturated palmitic and stearic fatty acids in H. anomalus averaged 84 g/kg, about 25 g/kg less than in cultivated sunflower oil (110 g/kg), while H. deserticola averaged 100 g/kg. Helianthus anomalus has the largest achenes and the highest oil concentration of any of the wild sunflower species. This will facilitate breeding when introducing genes from this wild annual progenitor into cultivated sunflower. The lower saturated fatty acid profile is also a desirable trait offering the potential to reduce saturated fatty acids in cultivated sunflower by introducing genes from the wild species. Further research will be needed to determine the inheritance of the fatty acids and oil content. Other agronomic traits will need to be monitored during the introgression of these traits into cultivated sunflower.