New germplasms enable high oleic acid sunflowers

Food producers are increasingly turning to vegetable oils in their formulations in place of partially hydrogenated oils and fats, which are sources of harmful trans- and saturated fatty acids. The development of the HA 458, HA 459 and HA 460 lines by researchers at the USDA's Agricultural Research Service (ARS) and North Dakota Agricultural Experiment Station will be ultimately result in oil for the food industry that boasts better flavour, shelf life and frying stability thanks to the high levels of oleic fatty acid. Changing the fatty acid structure of sunflower oil has been a target of the National Sunflower Association (NSA) for more than a decade. In 1995 its members made a commitment to developing oils to meet food industry needs - that is, an oil with "a pleasing taste, stability without needing partial hydrogenation and low saturated fat levels". The NSA was supported in this endeavour by USDA plant breeders, as well as the food industry and sunflower growers. An earlier breakthrough came in the form of Archer Daniel Midland's NuSun, a mid-oleic oil commercially available since 2003. NuSun is said have less than 10 per cent saturated fat than linoleic sunflower oil and oleic levels of between 55-75 per cent. Information on the precise oleic acid levels enabled by the ARS breakthrough were not available at time of publication, but it looks likely that they will build on the efforts already in place. But before the oil gets as far down the food supply chain as manufacturers, it will be growers who will feel the benefit of the germplasm's disease resistant traits, since they will help to reduce crop wastage. Downy mildew is caused by a fungus called Plasmopara halstedii​. It affects both seedlings and mature plants, causing cotton-like growths on the former and clublike roots and stunted growth in the latter. According to ARS, a fungicide called metalaxyl has previously been used to combat the fungus, but since it has built up a resistance and 15 new races of downy mildew have been identified, the new germplasms have been called "invaluable".​ The development has taken 20 years to come to fruition, during which time the researchers crossed elite sunflower lines with wild plants collected from Idaho and Texas. In fact, the ARS has been involved in collecting and researching wild sunflowers since 1976. It uses the genes in wild seeds as a tool to combat issues that impair crop volume and quality, such as pests and diseases. At the service's Sunflower Research Unit in Fargo, North Dakota, there are more than 50 species of Helanthus. The unit acts as a clearing house for specimens, where seeds are evaluated for weight, oil content and fatty acid composition prior to being catalogued and stored at the National Plant Germplasm System in Ames, Iowa. This is not the first time the ARS has developed new sunflower germplasm lines to overcome issues affecting crops. In 2004 it released three others, known as RHA 439, RH 440 and HA 441, intended to fight sclerontinia sclerotiorum​, a disease that causes stalk and head rot in the plants. ARS plant pathologist Tom Gulya said at the time he expected new commercial cultivars bred from the lines to suffer far less damage from the fungus in the future. As of the end of 2004, the ARS estimated that the economic value of traits bred into cultivated sunflower from wild species to be between US$267m and $384m per annum.