Submitted to: Sunflower International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 12, 2000
Publication Date: N/A
Interpretive Summary: Plant genetic resources management comprises several phases including germplasm collection and maintenance. Collection is the first step to gather the germplasm into the genebank for safe keeping. The next important step is to maintain the genetic integrity in the germplasm collection. This is a priority when regenerating populations for increasing seeds for distribution. The wild sunflower germplasm collection is stored and maintained at the USDA Agricultural Research Service, North Central Regional Plant Introduction Station, Ames, IA. Several accessions have been evaluated for fatty acid composition of the oil. These evaluations were performed on the oil from seeds from the original populations. Since we know that fatty acids in sunflower are environmentally influenced, we designed a study to evaluate the fatty acid composition in populations that had been regenerated for seed increase in the routine maintenance of the collection. The largest number of populations of a species examined was from the wide ranging wild annual species, H. annuus. This species had a significant decrease in palmitic and stearic acids, and an increase in oleic acid , and no change in linoleic acid for the regenerated populations compared to the original populations. For the perennial species evaluated, only H. nuttallii had a significant increase in oleic and significant decrease in linoleic acids. It appears that selection for specific fatty acids in oil of certain species will require analyzing both the original and regenerated populations before determining which populations should be utilized in a selection and breeding program.
Technical Abstract: One goal of plant genetic resources conservation is to preserve the genetic integrity of individual populations. Since oil quality is environmentally influenced and evaluation for this characteristic is usually performed on oil from achenes from the original populations of wild sunflowers, a study was conducted to compare oil quality of the original populations with populations regenerated for accession maintenance. Five annual species, Helianthus annuus, H. debilis, H. petiolaris, H. praecox, and H. niveus, and four perennial species, H. decapetalus, H. divaricatus, H. giganteus, and H. nuttallii were evaluated for four major fatty acids, palmitic, stearic, oleic, and linoleic acids. There were significant differences between the original and the regenerated populations for palmitic, stearic, and oleic acids in H. annuus. In H. debilis and H. praecox, there were significant differences in oleic and linoleic acids, but not in palmitic or stearic acids. In H. niveus, there were significant differences in stearic and oleic acids. Original and regenerated populations of Helianthus petiolaris did not differ in oil quality. For the perennial species, only H. nuttallii had a significant difference in oleic and linoleic acids. It appears that for certain fatty acids in some species caution will need to be exercised when assessing the potential oil quality of original populations and those regenerated for genebank maintenance.