Submitted to: Proceedings Sunflower Research Workshop
Publication Type: Proceedings
Publication Acceptance Date: 1/30/1998
Publication Date: N/A
Interpretive Summary: Plant genetic resources management comprises several phases including germplasm collection and maintenance. Collection is the first step to put the germplasm in a genebank for safe keeping. The next important step is to maintain the genetic integrity in the germplasm collection. This is a top priority when regenerating populations for seed in crosses during maintenance. Wild sunflower germplasm is stored and maintained at the USDA Agricultural Research Service North Central Regional Plant Introduction Station, Ames, IA. Several of the accessions in the wild sunflower collection have been evaluated for fatty acid composition of the oil. These evaluations were done on the original collections. Since we know that fatty acids in sunflower are environmentally influenced, we designed a study to evaluate fatty acid composition in populations that had been regenerated for seed increases in routine maintenance of the collection. The largest number of populations examined were from wild H. annuus which had a significant decrease in palmitic and stearic acid and an increase in oleic acid and no change in linoleic acid in regenerated populations compared to the original populations. The results would indicate that one would have to evaluate both populations to get an accurate assessment of the fatty acid for selection and breeding.
Technical Abstract: One goal of plant genetic resources conservation is to preserve the genetic diversity in individual populations. Since oil quality is known to be environmentally influenced and evaluation for this characteristic is usually done on achenes from the original population in wild sunflower, a study was conducted to compare oil composition between the original populations and those regenerated for maintenance purposes. Four annual species, Helianthus annuus, H. petiolaris, H. debilis, and H. praecox and three perennial species H. giganteus, H. nuttallii, and H. tuberosus were evaluated for four major fatty acids, palmitic, stearic, oleic, and linoleic acids. In H. annuus there was a significant decrease in palmitic and stearic acids, an increase in oleic acid and no change in linoleic in the regenerated populations compared to the original populations. Regenerated populations of H. debilis and H. praecox had a significant decrease in oleic acid and a significant increase in linoleic acid, but no significant difference for palmitic and stearic acids. Helianthus petiolaris accessions did not differ in oil composition between the original and the regenerated populations. Since only one population of each perennial species was available for analysis, no statistical comparison can be made. It appears that selection for specific fatty acids in certain species will require analysis of both the original and regenerated populations before selecting the population which to continue selection and breeding.