Construction Of A Mapping Population With Quality Traits And Analysis Of SSR Markers Linked To QTLs For Seed Protein And Oil Content In Soybean

Soybean seeds contain abundant protein and oil, which is a kind of important plant oil and the major source of plant protein with high quality. At present, the soybean variety with high protein or high oil is absent in our country. So it is an urgent task to improve the content of soybean oil and protein using modern biology and breeding technology. Because these two traits are the quantitative traits controlled by many genes/loci, it is useful for QTL mapping in the way of application. In this study, a F2 segregating population was constructed, and several SSR markers associated with loci for seed protein and oil content were screened using this population in order to improve soybean quality by using Marker-assisted selection. The main results of the study were summarized as follows:1. A F₂ population with the double-quality traits was developed from a cross between KF14 and S8510. This population contained 287 plants. KF14 seeds have higher protein and lower oil content, whereas seeds of S8510 have higher oil and lower protein content. The oil and protein content of seeds of F₂ segregating population all appeared a great segregation that exceeded their parents. They all accorded with the normal distribution.2. Among a total of 433 pairs of SSR primers used in this experiment, 109 primer pairs were detected to own polymorphisms between genomes of parents, KF14 and S8510. The frequency of polymorphisms was 25%.Among 109 primer pairs, 6 pairs,Satt331, Satt551, Satt572, Satt290, Satt202 and Satt323, were polymorphic between two protein-pools, 4 pairs,Satt472, Satt345, Satt204 and Satt429, possessed polymorphisms between two oil-pools.3. By using SSR technology and bulked segregation analysis (BSA), and linkingwith prominence analysis, 2 pairs of SSR primers, Satt202 and Satt551, were identified to be associated with seed protein content. 2 pairs of SSR primers, Satt345 and Satt472, were identified to be related to seeds oil content. Satt202 and Satt551 explained the phenotypic variation of 3.8% and 3.1%, respectively. Satt345 and Satt472 explained the phenotypic variation of 1.7% and 3.7%, respectively.4. A group of soybean materials, which were pure genotype and contained higher protein or higher oil content in seeds, were amplified and detected by using these markers. The results were as follows: in more than 80% of the materials with higher seed protein or oil content, which came from the same ecological regions as parents, a specific marker band for the QTL could be detected. About 30% of the material that came from the different ecological regions, the specific marker for the QTL could be found. The results showed that the identified SSR markers would be useful in soybean breeding program.