Title: Utilizing real-time PCR to reveal ahFAD2 genotypes in segregating peanut populations. Authors
Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 17, 2010
Publication Date: July 13, 2010
Citation: Barkley, N.L., Wang, M.L., Pittman, R.N. 2010. Utilizing real-time PCR to reveal ahFAD2 genotypes in segregating peanut populations.. American Peanut Research and Education Society Abstracts. 42:21. Technical Abstract: Oleic acid (C18:1), a monounsaturated, omega-9 fatty acid is an important agronomic trait in peanut cultivars because it provides increased shelf life, improved flavor, enhanced fatty acid composition, and a beneficial effect on human health. Consequently, an emphasis has been placed on breeding peanuts with high levels of oleic acid and low levels of linoleic acid (C18:2), a polyunsaturated, omega-6 fatty acid. In an attempt to increase genetic diversity, specifically disease resistance of high oleic acid lines, crosses between lines containing high oleic to linoleic ratios (high O/L), wild species, and cultivated botanical varieties (Arachis hypogaea ssp. hypogaea var. hirsuta or peruviana) were prepared. The main bottleneck of breeding research is rapid detection of the trait(s) of interest. Therefore, genotyping assays were developed to detect wild type and mutant alleles in both ahFAD2A and ahFAD2B, which are known to affect oleic acid (C18:1) and linoleic acid (C18:2) levels. Total fatty acid composition and the ahFAD2 genotypes were determined in the parents and the progeny of four crosses, as well as, some selected peanut germplasm. The O/L ratio varied from 0.85 to 61.28 in the four crosses evaluated. The oleic acid trait segregated in a digenic (15:1) or a monogenic (3:1) manner dependent on the genotype of the parents used in the cross. Statistical analysis demonstrated that oleic acid was negatively correlated with linoleic and palmitic acid (C16:0), but positively correlated with two long chain fatty acids, gadoleic (C20:1) and lignoceric acid (C24:0). Combining the fatty acid profiles determined by gas chromatography with each individual’s genotype provides valuable insight on the effect of each genotype on the oleic acid and correlated fatty acid content in peanut seeds.