Author
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Seiler, Gerald |
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Submitted to: International Symposium on Sunflower in Developing Countries
Publication Type: Proceedings Publication Acceptance Date: 4/10/2002 Publication Date: 5/1/2002 Citation: SEILER, G.J. WILD SUNFLOWER GERMPLASM: A PERSPECTIVE ON CHARACTERISTICS OF USE TO SUNFLOWER BREEDERS IN DEVELOPING COUNTRIES. INTERNATIONAL SYMPOSIUM ON SUNFLOWER IN DEVELOPING COUNTRIES. 2002. www.ISA.cetiom.fr/symposium/seiler.htm Interpretive Summary: Development of cultivated sunflower from wild species had resulted in individual plants being selected over many years by early agriculturists on the basis of reproductive potential, adaptation, and the preferences of those involved with seed production. Domestication of the crop thus resulted in fewer gene combinations or less genetic diversity than the species as a whole. This has produced a crop with a narrow genetic base, which could benefit from utilization of wild relatives of the cultivated crop. The future competitiveness of the sunflower industry in developing countries will rely on the development of new technologies and novel methods to enhance the utilization of wild sunflower germplasm. Wild Helianthus species constitute the genetic stock from which cultivated sunflower originated. The genus Helianthus contains 50 species and 19 subspecies, with 14 annual and 36 perennial species. All species are native to North America. They have contributed useful characteristics for sunflower improvement. Species are adapted to a wide diversity of habitats and possess considerable variability for most economic and agronomic characteristics, insect and disease resistance and seed quality factors. This is particularly important when production is expanding into new areas, subjecting the crop to intensified disease and insect problems and extremes in environmental conditions. Development of the CMS hybrid system from wild H. petiolaris has facilitated the use of wild sunflower species in breeding programs by allowing the hybridization of genetically distant species and the subsequent incorporation of specific characteristics for the improvement of cultivated sunflower. There is a continued need to collect, maintain, evaluate and enhance wild Helianthus germplasm for future utilization in cultivated sunflower. The genetic diversity of the wild species can make a significant contribution to sunflower in developing countries by providing genes for resistance (tolerance) to pests and environmental stresses, allowing the crop to become and remain economically viable. Technical Abstract: Sunflower is produced on 15 million hectares in 40 countries worldwide. It is the fourth largest edible oilseed crop and the second largest hybrid seed crop. The large geographic area on which sunflower is produced requires the crop to be very adaptable to many stresses including diseases, insects, and environmental factors. Wild relatives of cultivated sunflower are genetically diverse and are readily available for genetic improvement of the crop. The wild sunflower gene bank has over 2100 accessions with 50 species, 14 being annual and 36 perennial species. Sunflower as a cultivated crop has a long history of utilizing both wild and cultivated germplasm to increase its genetic diversity and economic value. In the USA alone, the economic impact of the sunflower industry is 2.6 billion dollars annually, of which the wild species contribute an estimated 269.2 million dollars. Wild species are the source of the male sterile cytoplasm used in most commercial hybrids, and of several resistance genes for prevalent sunflower pathogens. The wild paradoxical sunflower is the source of a dominant gene for salt tolerance that has been incorporated into cultivated sunflower. Peredovik, PI 287231, is a high oil cultivar introduced from the former Soviet Union that forms the basis of high oil sunflower used worldwide. It was developed from wild Jerusalem artichoke populations over 40 years ago. Populations of some wild annual sunflowers have a high frequency of genes for resistance to rust and downy mildew. A few species have been used to modify fatty acid profiles in sunflower. While many genes from wild sunflowers have been identified and used in cultivated sunflower, many genes remain to be discovered for new and evolving challenges that may not even exist today making the crop an adaptable, viable, and sustainable no matter where it is grown. |
