Molecular mapping and identification of soybean fatty acid modifier quantitative trait loci

Altering FA content in soybean [Glycine max (L.) Merr.] oil for improved functionality is a research goal of many soybean breeders. Several of the genes that alter palmitic, stearic, oleic, linoleic, and linolenic acids are modifier genes with small effects, causing these FA traits to act as quantitative traits. The objective of this study was to identify modifier FA quantitative trait loci (QTL) in soybean. A recombinant inbred line population was created from two prominent ancestors of currently available U.S. cultivars (Essex and Williams) and grown in five environments. One hundred simple sequence repeat markers spaced throughout the genome were mapped in this population. QTL were found for all five FA traits on the soybean linkage groups C2, D2, D1b, F, K, and L. A single marker interval on linkage group L contained the largest QTL for palmitic (r(2) = 13.1%), oleic (r(2) = 35.3%), linoleic (r(2) = 50.5%), and linolenic acids (r(2) = 24.8%); however, this interval also contained the gene for growth habit (Dt1) and was significantly associated with maturity. Other modifier QTL found in this study may be of use in marker-assisted selection to enable breeders to increase genetic gains for desirable FA composition of soybean.