Title: Improving fatty acid composition in peanuts (Arachis hypogaea) by SNP genotyping and traditional breeding. Authors
Submitted to: Gordon Research Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 17, 2010
Publication Date: July 19, 2010
Citation: Barkley, N.L., Wang, M.L., Pittman, R.N. 2010. Improving fatty acid composition in peanuts (Arachis hypogaea) by SNP genotyping and traditional breeding.. Gordon Research Conference Proceedings. July 2010. Technical Abstract: Fatty acid composition is an important seed quality trait in cultivated peanuts (Arachis hypogaea L.). Monounsaturated fats, such as oleic acid (C18:1), an omega-9 fatty acid, has been shown to have beneficial effects on human health. In addition, peanuts bred to produce high levels of oleic acid (>75%) have an increased shelf life and improved flavor. Due to the beneficial effects of oleic acid, an emphasis has been placed on breeding peanuts with high oleic acid and low levels of linoleic acid (C18:2), a polyunsaturated, omega-6 fatty acid. Therefore, crosses between lines containing high oleic acid and peanut lines carrying disease resistance were prepared in an effort to produce high oleic disease resistant peanuts. One of the main hurdles of breeding, however, is the identification of the desired genotypes/phenotypes and elimination of undesirable genotypes/phenotypes. In peanuts, the high oleic trait is controlled by the inheritance of two key SNP mutations (G448A and 442insA) in two homoeologous genes ahFAD2A and ahFAD2B, respectively. These genes normally produce an enzyme known as microsomal oleoyl-PC desaturase which catalyzes the conversion of oleic to linoleic acid. High oleic peanuts will only be produced if these two SNP mutations are homozygous recessive which significantly reduces the desaturase activity. Genotyping assays utilizing real-time PCR have been developed to detect these key mutations from the wild type using either seed or leaf material. Four segregating F2 populations have been genotyped and their total fatty acid composition was assessed by gas chromatography. High oleic peanuts, as well as F2 lines still segregating for the high oleic trait, have been identified in these four populations and are being evaluated in the field for disease resistance.