Quantitative trait loci analysis of soluble sugar contents in soybean

The soluble sugar content in soybean seeds, mainly sucrose, stachyose, raffinose and trace amounts of glucose and fructose, is important for the increasing global market demand for various soyfoods including tofu, soymilk, natto, bean sprouts and edamame due to their nutritional value and health benefits. The objective of this study was to conduct quantitative trait loci (QTL) analysis and identify molecular markers for soluble sugar content in soybean seeds for marker-assisted selection (MAS) in soybean breeding. The content of the five previously mentioned sugars were measured and associated QTLs were mapped based on a F-2 population that was derived from a cross between V97-3000 and V99-5089. Eleven QTLs were detected for the five sugar contents: one for glucose, three each for fructose and sucrose, and two each for raffinose and stachyose. However, only one QTL for sucrose, one QTL for raffinose, and two QTLs for stachyose were identified with LOD > 3.0 and R-2 > 10% from this research. The QTL on chromosome 11 [linkage group (LG) B1] was identified as associated with sucrose, raffinose and stachyose in the same region as previously reported for sucrose and stachyose. The SSR marker, Satt359, on the QTL B1 region had an significant association with sucrose (LOD = 5.192; R-2 = 0.134), raffinose (LOD = 3.95; R-2 = 0.104), and stachyose (LOD = 13.572; R-2 = 0.314); therefore it can be used to assist breeding selection for sucrose, raffinose and stachyose contents simultaneously.