Confirmation of Fatty Acid Modifier QTL in Soybean.

Soybean [Glycine max (L.) Merrill] oil primarily contains the following fatty acids: palmitic, stearic, oleic, linoleic, and linolenic. The concentration and characteristics of each fatty acid determine the quality of products produced. For example, linolenic acid is prone to oxidation, which turns the oil product rancid thus reducing its shelf life. Breeding soybeans which have specific fatty acid content is important for edible oil and industrial purposes. Several modifier genes have been found to influence palmitic, stearic, oleic, linoleic and linolenic acid content in soybean. . The purpose of this study was to confirm previously reported quantitative trait loci (QTL) for fatty acid modifier genes in an independent ‘Essex’ x ‘Williams 82’ population, and to report novel fatty acid QTL which may be submitted to Soybase for future breeding studies.. Fatty acid analyses by gas chromatography of the methyl esters for 131 F6 derived recombinant inbred lines (RIL) and the two parents were performed. The RILs averaged 124, 42, 245, 531, and 59 g kg-1 for palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid, respectively. Parents were screened with 203 SSR markers on linkage groups (LGs) B2, C2, D1a, D1b, D2, F, G, H, I, K, L and M, previously associated with fatty acid modifier QTL. Polymorphisms were found between the parents for 70 of 117 SSR markers that amplified in the RILs. Single factor ANOVA analysis was used to identify QTL. Fatty acid modifier QTL were confirmed as follows: palmitic acid [LG D2 (Satt372), LG L (Satt166, Satt561 and Satt229)], stearic acid [LG B2 (Satt070, Satt556, Satt304 and Satt474), LG C2 (Satt557, Satt460, Satt079, Satt307), LG L (Satt481, Satt1156, Satt076, and Satt166)], oleic acid [LG L (Satt076, Satt166, Satt527, Satt561, Satt229)], linoleic acid [LG F (Satt335), LG L (Satt076, Satt166, Satt527 and Satt561)], linolenic acid [LG L (Satt481, Satt156, Satt076, Satt166, Satt527 and Satt561)]. Thus, we were able to validate previously reported agronomic trait QTL to guide molecular breeders, and provide evidence for novel QTL that may affect further genetic gains in soybean.