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Quantitative trait locus analysis of saturated fatty acids in a population of recombinant inbred lines of soybean

Jiang, Guo-Liang, Wang, Xianzhi, Green, Marci, Scott, Roy, Hyten, David, Cregan, Perry
Molecular breeding 2012 v.30 pp. 1163
Glycine max, crops, crossing, fatty acid composition, genotype-environment interaction, genotyping, inbred lines, industrial applications, marker-assisted selection, microsatellite repeats, palmitic acid, plant breeding, quantitative trait loci, seeds, single nucleotide polymorphism, soybean oil, soybeans, stearic acid, vegetable oil
Soybean [Glycine max (L.) Merr.] is an important crop which contributes to 57.7% of the world’s oilseed production. Palmitic and stearic acids are two predominant saturated fatty acids in soybean oil. Different levels of saturated fatty acids are desired depending upon the uses of the soybean oil. Vegetable oil low in saturated fatty acids is preferred for human consumption; while for industrial applications, soybean oil with higher levels of saturated fatty acids is more suitable. The objectives of this study were to identify quantitative trait loci (QTLs) for saturated fatty acids, analyze the genetic effects of single QTLs and QTL combinations, and discuss the potential of marker-assisted selection in soybean breeding for modified saturated fatty acid profiles. A population of recombinant inbred lines (RILs) derived from the cross of SD02-4-59 × A02-381100 was grown in five environments and the seed samples from each environment were evaluated for fatty acid content. Genotyping of the population was performed with 516 polymorphic single nucleotide polymorphism (SNP) markers and 298 polymorphic simple repeat sequence (SSR) markers. Eight QTLs for palmitic acid, five QTLs for stearic acid and nine QTLs for total saturated fatty acids were detected by composite interval mapping (CIM) and/or interval mapping (IM), with a high level of consistency or repeatability in multiple environments. Most of these QTLs have not been reported previously, with the exception of qPAL-A1 which confirmed the result of a previous study. Significant QTL × QTL interactions were not detected. However, significant QTL × environment interactions were detected in most cases. Comparisons of two-locus and three-locus combinations indicated that cumulative effects of QTLs were significant for both palmitic and stearic acids. QTL pyramiding by molecular marker-assisted selection would be an appropriate strategy for improvement of saturated fatty acids in soybean.