Study of Genetic Associations of Black Seed Coat Trait in Mutant Soybean Line DT26BS

The research project Study of Genetic Associations of Black Seed Coat Trait in Mutant Soybean Line DT26BS forms part of the IAEA Coordinated Research Project D24015, entitled "Radiation-induced crop diversity and genetic associations for accelerating variety development", in accordance with the terms and conditions of the IAEA Research Contract No. 25156.Black seed coat in soybean is controlled by multiple classical genetic loci, such as I, T, W1, R, and O. Three independent loci (I, R, and T) mainly control the biosynthesis of pigments that determine seed coat color. Recently, two highly similar and co-expressed UF3GT genes (Glyma07g30180 and Glyma08g07130) were shown to be expressed in the seed coats of black-seeded soybean lines. These genes specifically transfer a glucose moiety to the cyanidin molecule at the 3'-hydroxyl group, resulting in the formation of cyanidin-3-glucoside.Several natural mutations associated with seed coat color have been selected in soybean cultivars. These mutations represent an important source of genes for the development of food-type soybean cultivars in breeding programs. One method for identifying mutations is gene mapping. Genetic linkage mapping is a prerequisite for understanding the inheritance of traits at the genome level. Accurate mapping of quantitative trait loci (QTLs) and candidate genes has traditionally relied on high-resolution genetic association maps. In recent years, high-throughput next-generation sequencing (NGS) technologies have enabled the construction of high-density SNP genetic maps, improving genome assembly and map-based gene identification.In Vietnam, mutant soybean varieties are mainly created by gamma irradiation and identified based on phenotypic changes compared with the original varieties. To date, no in-depth molecular studies of these mutant traits have been conducted. Mutants are important genetic resources for understanding gene function and breeding. Therefore, understanding germplasm genetic diversity is essential for developing effective strategies to improve soybean economic traits. Using irradiation-induced mutation, the Agricultural Genetics Institute developed the mutant black soybean line DT26BS from the yellow soybean variety DT26. Compared with the original variety, the mutant line shows similar agro-biological characteristics, except for the black seed coat trait.