The aim of the present study is to evaluate the absolute content and accumulation patterns of flavonoid components; to give insight into the accumulation relationships among flavonoid components; to explore the correlation between the content of flavonoid components and the expression of flavonoid biosynthesis genes in Tartary buckwheat seeds; and to construct a biosynthetic pathway on the major flavonoid components in Tartary buckwheat seeds. In total, 61 flavonoid components were absolutely quantified in five Tartary buckwheat varieties, of which 41 existed in all varieties. The content of most flavonoids varied significantly among different varieties or within the same variety. Rutin, quercetin, nicotiflorin, and kaempferol were the dominant flavonoid components in the Tartary buckwheat seeds, accounting for 73.05–81.79% of the total flavonoids. Significantly positive or negative correlations with content accumulation were found between some flavonoid components. Thirty-six flavonoid components displayed four different accumulation patterns in the developing Tartary buckwheat seeds. Seventeen structural genes for flavonoid biosynthesis displayed a significantly positive correlation with the accumulation of most flavonoid components during the development of Tartary buckwheat seeds, and the F3′5′H-3 gene might be the most crucial contributor in determining the total flavonoid content in Tartary buckwheat seeds. A schematic of the biosynthesis pathways for 30 major flavonoids in Tartary buckwheat seeds was constructed. These findings provide an outlook of the flavonoid components and their biosynthesis in Tartary buckwheat seeds and have potential applications in breeding new cultivars with higher flavonoid contents.

Tartary buckwheat is an important medicinal and edible crop known for its significant health benefits to humans. While numerous Tartary buckwheat germplasm resources have been collected in China, the genetic diversity and core germplasm resources remain largely unclear. The aim of this work was to analyze the genetic variability and construct a core germplasm collection of Tartary buckwheat. Fifteen highly polymorphic SSR markers were used to investigate 659 Tartary buckwheat accessions. A total of 142 alleles were marked, with an average of 9.47 alleles per locus. Genetic variability analysis revealed that these collected accessions exhibit high genetic diversity and can be classified into seven subgroups. Among wild, landrace, and improved accessions, the wild accession showed the highest genetic diversity, while no significant genetic variation was observed between the landrace and improved accessions. Based on genetic diversity and population structure analyses, a core germplasm collection containing 165 accessions (47 wild, 92 landrace, and 26 improved) was constructed, ensuring high genetic diversity and good representation. This study not only highlighted the genetic differences among Tartary buckwheat accessions, but also provided insights into the population structure and the development of a core germplasm collection. It provided important references for the conservation of genetic diversity and the genetic improvement of Tartary buckwheat.