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.

Tartary buckwheat has increasingly become the focus of people’s attention due to its powerful health benefits. Golden buckwheat is a traditional Chinese medicine. People have begun to utilize it through wide hybridization to further enhance the health benefits of Tartary buckwheat. To study the genetic stability of the interspecific hybrids of Tartary buckwheat with golden buckwheat, and to provide scientific basis for the interspecific cross breeding of buckwheat, the mitotic chromosomes of two buckwheat double lines and their interspecific hybrids with golden buckwheat were subjected to observe the karyotypes. The results showed as follows: (1) The two autotetraploid Tartary buckwheat lines (Long Black-4T and Daku-1) have chromosome number 2n = 32. The karyotype formula of 2n = 4x = 32 consisted of 16 pairs of metacentric chromosomes for Long Black-4T (TTTT) while Daku-1 (TTTT) has 1sm + 7m Gui Jinqiao 4 with 2n = 32 has a karyotype formula of 2n = 4x = 32 that consisted 1sm + 6m + 1M (genome M) and 2sm + 5m + 1M (genome M’). The normal fertile tetraploid hybrid F1 plants between Long Black-4T and Gui Jinqiao 4 has 2n = 4x = [1sm + 7m (M), 1sm + 7m (M’), 14m + 2M (TT)]. The normal fertile variety Gui Jinku 1 from the above hybrid progenies shows 2n = 4x = [3sm + 5m (M), 2sm + 6m (M’), 16m (TT)], indicating an increment of sm chromosomes by rearrangements of chromosome structure in the M and M’ genomes. The above parents and their hybrids with the MM’TT genome show fertility. A plant from F2 of the above cross, showing highly infertility, has 2n = 3x= [1sm + 7m (M), 1sm + 7m (M’), 8m (T)]; and back cross progeny plant from Daku 1/Gui Jinqiao 4 F2//Gui Jinqiao 2 golden buckwheat has 2n = 4x = [16m (MM), 5sm + 3m (M’), 1sm + 7m (T)], showed high infertility, which is caused by genome aneuploidy and non-even ploidy. The above shows that there are obvious variations of genome karyotypes from the same parent, indicated by certain chromosome structural rearrangements in genomes T, M, and M’.