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United States Department of Agriculture

Agricultural Research Service

Title: Two-Year Study on the Inheritance of Reduced Saturated Fatty Acid Content in Sunflower Seed

Authors
item Vick, Brady
item JAN, CHAO-CHIEN
item Miller, Jerry

Submitted to: Helia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 22, 2004
Publication Date: December 1, 2004
Citation: Vick, B.A., Jan, C.C., Miller, J.F. 2004. Two-year study on the inheritance of reduced saturated fatty acid content in sunflower seed. Helia. 27(41):25-40.

Interpretive Summary: Studies have shown that high levels of saturated fat consumption are correlated with increased risk of coronary heart disease. Traditional sunflower oil has about 13% saturated fatty acids, which is considered low compared to most vegetable oils. However, canola oil is lower with about 7% saturated fatty acids, and remains a major competitor to sunflower oil in the market place. RS1 and RS2 are two USDA-ARS genetic stocks that have reduced saturated fatty acid content. In this two-year study, we report on the inheritance of palmitic and stearic acids, the two most abundant saturated fatty acids in sunflower oil, in crosses of RS1 and RS2 with a traditional line used in making sunflower hybrids. This line has a fatty acid composition similar to many commercial sunflower hybrids. Our experiments showed that the F2 seed (the seed that is harvested by the farmer and sent to the processor) of crosses of RS1 or RS2 with the traditional line was intermediate between the two hybrid parents in saturated fatty acid content. The results showed that the inheritance and expression of the reduced palmitic and stearic acid traits of RS1 and RS2 were complex and determined by more than one gene. In addition, there were significant relative changes in palmitic and stearic acid contents between the two growing seasons of 2002 and 2003, suggesting that environmental conditions play a significant role in the relative proportions of palmitic and stearic acids. The total saturated fatty acid content was also influenced by environment, producing opposite effects with RS1 (higher total saturated fatty acids in 2003) and RS2 (lower total saturated fatty acids in 2003). Thus, it can be expected that the level of saturated fatty acids in cultivated hybrid sunflower with RS1 or RS2 as one of the hybrid parents will vary somewhat from year to year. The results of the study demonstrate that it will be necessary to incorporate the reduced saturated fatty acid trait into both parents of a hybrid in order to achieve the lowest possible concentration of saturated fatty acids in the F2 seed.

Technical Abstract: RS1 and RS2 are two genetic stocks that have reduced saturated fatty acid content. In this two-year study, we report on the inheritance of palmitic and stearic acids of RS1 and RS2 in the F1 and F2 generations of crosses with HA 382, an inbred line with a fatty acid composition similar to many commercial sunflower hybrids. The expression of the reduced palmitic and stearic acid traits is most important in the second generation of a hybrid cross (F2 seed) because it is the F2 seed that is harvested by the farmer, sold, and crushed for the oil. Our experiments showed that the F2 seed of reciprocal crosses of RS1 or RS2 with HA 382 was intermediate between the two hybrid parents in saturated fatty acid content. The results showed that the inheritance and expression of the reduced palmitic and stearic acid traits of RS1 and RS2 were complex and determined by more than one gene. In addition, there were significant relative changes in palmitic and stearic acid contents between the two growing seasons of 2002 and 2003, suggesting that environmental conditions play a significant role in the relative proportions of palmitic and stearic acids. The total saturated fatty acid content was also influenced by environment, producing opposite effects with RS1 (higher total saturated fatty acids in 2003) and RS2 (lower total saturated fatty acids in 2003). Thus, it can be expected that the level of saturated fatty acids in cultivated hybrid sunflower with RS1 or RS2 as one of the hybrid parents will vary somewhat from year to year. The results of the study demonstrate that it will be necessary to incorporate the reduced saturated fatty acid trait into both parents of a hybrid in order to achieve the lowest possible concentration of saturated fatty acids in the F2 seed.

Last Modified: 9/10/2014
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