Abstract: Soybean [Glycine max (L.) Merr., 2n=2x=40] is grown worldwide, especially in the United States, Brazil, Argentina, and China. Increasing oil content in soybean seeds is one of the main aims in soybean breeding. Oil content is quantitative traits controlled by multiple genes. Many researches have used molecular markers to map quantitative trait loci (QTL). Currently, SoyBase (2007) contains at least 68 QTL associated with oil content that have been mapped in many different populations and environments. The development of molecular tools has facilitated the task of identifying chromosomal regions related to particular traits. Song et al. (2004) developed an integrated genetic map spanning 2 523.6 cM across 20 linkage groups that contained 1 849 markers, including 1 015 SSRs, 709 RFLPs, 73 RAPDs, 24 classical traits, 6 AFLPs, 10 isozymes, and 12 others. In MAS, it would be more desirable to use confirmed QTL. For this purpose, it is necessary to conduct QTL, mapping studies in as many and as diverse environments and population as feasible. In this study, QTL of soybean oil content in five different years was analyzed with a recombination inbred lines (RIL) population derived from a cross between Charleston and Dongnong 594 by mixed linear model approach. 11 QTL with additive effects for oil content were mapped in the linkage groups A1, A2, B1, C2, D1a, D1b, F, H, and O. 15 QTL pairs with epistatic effects for oil content in the RIL were detected, and the general phenotypic variation was 17.84%. 9 QTL were detected from QTL× environment interaction, and the general contribution was 5.76%.

Key words: Soybean, Oil content, Mixed linear model, QTL × environment interaction, Epistatic effects