Author
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Seiler, Gerald |
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Gulya Jr, Thomas |
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Submitted to: Proceedings Sunflower Research Workshop
Publication Type: Proceedings Publication Acceptance Date: 3/15/2004 Publication Date: 3/15/2004 Citation: Seiler, G.J., Gulya Jr, T.J. 2004. Exploration for wild Helianthus exilis, an endemic serpentine sunflower of California. Proceedings Sunflower Research Workshop. Available: http://www.sunflowernsa.com/research/research-workshop/documents/137.pdf Interpretive Summary: 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. The disappearance of habitat for several wild sunflower species is of concern for the long-term survival of the sunflower industry because wild species are the ancestors of the crop. Therefore, it is imperative that as many natural populations of wild species as possible be collected and preserved in germplasm collections for future use. There has been an increased interest in breeding sunflower for arid regions and low nutrient soils. Endemic serpentine sunflower is an excellent candidate based on its adaptation to these types of environments. Unfortunately, due to the demand for the seed of these species and the difficulties of regenerating the original populations, seed has not been available for research for almost 20 years. The objective of this study was to collect populations of serpentine sunflower and to make them available for further research. The exploration covered 2,600 miles in California, from the Coastal range north to the Oregon border, to the western foothills of the Sierra Nevada Mountains. Twenty-seven populations of serpentine sunflower were collected from the distribution of the species covering 1,100 square miles of serpentine soil in California. The general habitats where the species was found include serpentine outcrops, alluvial streambeds, rocky ravines, serpentine meadows and seeps, and on occasion along edges of flowing streams. The successful exploration makes seed of serpentine sunflower available for research for the first time in over 22 years. The addition of these populations of wild species to the wild sunflower germplasm collection will insure their preservation for the future, and will greatly increase the available genetic diversity for improving the cultivated sunflower, keeping it a viable and competitive global crop. Technical Abstract: The genus Helianthus consists of 51 species (14 annual and 37 perennial), all restricted to North America. Serpentine sunflower, H. exilis, is endemic to the serpentine soils of the Coastal Range and Sierra Nevada mountains of California, which are generally arid and have low soil nutrients. This species is a potential source of useful genes for improving stress tolerance and adaptation to low soil nutrients for cultivated sunflower. The objective of this study was to collect populations of serpentine sunflower and make them available for further research. The exploration covered 2,600 miles in California, from the Coastal range north to the Oregon border, to the western foothills of the Sierra Nevada Mountains. Twenty-seven populations of H. exilis were collected from the range of the species covering 1,100 square miles of serpentine soil in California. An additional eight sites were visited, but no collections were made due to insufficient plants with seed. The general habitats where the species was found include serpentine outcrops, alluvial streambeds, rocky ravines, serpentine meadows and seeps, and on occasion along edges of flowing streams. The successful exploration makes seed of H. exilis available for research for the first time in over 22 years. These collections should provide sufficient variability representative of the genetic diversity of serpentine sunflower for future selection and improvement of cultivated sunflower. |
