Genetic Analysis And QTL Mapping Of Fatty Acid Composition Contents In Soybean

Modifying the fatty acid profile is one of the aims in soybean breeding program. The fatty acid composition of soybean seed affects the nutritional value,and the shelf life. The objective of this study was to evaluate the parents in cross breeding and map the areas of the soybean genome associated with fatty acid using simple sequence repeat (SSR) marker. Analyze the effects of QTL×environment interaction and epistemic effects. In this study, 314 samples of soybean germplasm resources from China or foreign were studied for their characteristics of fatty acid composition and its variation, also, the correlation between fatty acid composition and protein, fat. We select a group of valuable resource including"heidou"and"Jidou 12". There are differences in fatty acid composition between"heidou"and"Jidou 12". An F2 population of 120 lines from the cross of Jidou 12×Heidou was used as a mapping population using 87 SSR markers. Using composite interval mapping, quantitative trait loci (QTLs) for fat acid content were analyzed. F2:3 in Hainan and F2:4 in Gaocheng and Nanpi derived from the F2 population were used for confirmation. QTL×environment interaction and epistemic effects were analyzed by mixed linear model approach. The results were described as followed:1. The content of linoleic acid is high and the variation range is small in domestic varieties; Linolenic acid content variation is large; the correlativity between five kinds of fatty acids and protein,fat,is existed. The correlativity between linolenic acid, linoleic acid and oleic acid is stable.2. The variation of unsaturated fatty acids is mainly come from eco-types. In the average content of oleic acid,South spring soybean is highest,and 5.13% higher than Yangtze River spring soybean which is lowest; In the average content of linoleic acid,Yangtze River spring soybean is highest and 3.58% higher than Southern spring soybean which is lowest; In the average content of linolenic acid, Yangtze River spring soybean is highest and 2.19% higher than Southern summer soybean which is lowest; The variability from Nation bred variety is smaller than local variety.And we have selected a group of valuable resource. 3. A genetic map based on SSR markers is constructed with F2 population from the cross Jidou 12×Heidou. It spreads over 14 linkage groups and contains 66 SSR markers. 14 quantitative trait loci (QTLs) for fatty acid content were found in this population. One QTL accounted for 52% of variation in palmitic acid content. Three QTLs accounted for 7%-25%, explained 32% of total phenotypic variation for Stearic in F2, 31% in F2:4. Four QTLs accounted for 4%-20%,explained 31% of total phenotypic variation for Oleic in F2, 24% in F2:4. Two QTLs accounted for 12%-24% for Linoleic content. explained 36% of total phenotypic variation for Oleic in F2, 11% in F2:4. Four QTLs accounted for 9%-20% for Linolenic. 4 QTLs were confirmed in more than two environment,which controlled the Palmitic on D1a(r2=52%),and Stearic on C2 (r2=7%),and Oleic on A2 (r2=19%),and Linoleic on D1a (r2=24%) .4. QTL of soybean fatty acid content in four different environments was analyzed by mixed linear model approach. 4 QTLs with additive effect, dominance effect effects for fatty acid content were detected and these effects were all effected by environment interaction. They control Stearic, Oleic, Linoleic and Linolenic. The heredity value of effected by environment were 6.05%,2.96%,5.54%, and 2.89%. Two pairs of QTL with epistemic effects for fatty acid content in this population were detected. They were detected from QTL×environment interaction. A pairs of QTL on LG-F between sat₁33 and satt663 and LG-O between satt358 and satt445 control Stearic. One pair of QTL on D1a between sat₃53 and sat₄68 and A1 between satt684 and sat₃68 control Linoleic.